Blooming Blade - Triggering two times in one turn

[Zhari]

Hello, I got a question regarding the Cantrip Booming Blade.

My Cleric, casting Booming Blade, got the Warcaster feat.

Last sessions he used on his turn booming blade against a mob.
On the turn of the mob, it tried to get away from the cleric (first trigger of booming blade), while going around the cleric. the cleric uses his reaction (attack of opportunity) to cast the cantrip booming blade a second time,when the mob leaves his reach.
The mobs keeps moving and triggers it a second time.

You probably ask why he didnt stop before triggering a second time. The mob was low on hp and was trying to get away, but also had the second PC in grapple and wanted to drop him in a lavapool.

everything by the books? we were wondering because of the high amount of dmg that cantrip produced in one turn.:smallfrown:

thx for ur help :smallsmile:

[DivisibleByZero]

Depends on when your DM rules the first one to proc. Is it when the enemy begins his move, or when he actually leaves the space, or what?
I'd argue that it doesn't happen until he leaves the space, because until that point he hasn't actually moved. But that creates a problem.
The problem is that effects from the same spell do not stack. You have two different instances of the same spell going off at the same time from the same trigger. So by the RAW, only one of the BBs actually procs, and the second one potentially does nothing (again, dependent upon when your DM rules the first to proc). This is why I prefer WarCasters to have both BB and GFB. BB him, and when he moves you WC a GFB on him. Both go off, no discussion needed.

[Crusher]

Hello, I got a question regarding the Cantrip Booming Blade.

My Cleric, casting Booming Blade, got the Warcaster feat.

Last sessions he used on his turn booming blade against a mob.
On the turn of the mob, it tried to get away from the cleric (first trigger of booming blade), while going around the cleric. the cleric uses his reaction (attack of opportunity) to cast the cantrip booming blade a second time,when the mob leaves his reach.
The mobs keeps moving and triggers it a second time.

You probably ask why he didnt stop before triggering a second time. The mob was low on hp and was trying to get away, but also had the second PC in grapple and wanted to drop him in a lavapool.

everything by the books? we were wondering because of the high amount of dmg that cantrip produced in one turn.:smallfrown:

thx for ur help :smallsmile:

Yep, sounds good to me.

IMO, the real issue with that cantrip (along with GFB) is that it scales too well at higher levels. Yes, they have no effect-riders and they're restricted to melee-range, but even so gaining an extra die on both the initial hit and the second hit (via other target or moving) each time it jumps up gives a really high damage ceiling on spells that at least in theory are in competition with Acid Splash or Firebolt.

[Citan]

Hello, I got a question regarding the Cantrip Booming Blade.

My Cleric, casting Booming Blade, got the Warcaster feat.

Last sessions he used on his turn booming blade against a mob.
On the turn of the mob, it tried to get away from the cleric (first trigger of booming blade), while going around the cleric. the cleric uses his reaction (attack of opportunity) to cast the cantrip booming blade a second time,when the mob leaves his reach.
The mobs keeps moving and triggers it a second time.

You probably ask why he didnt stop before triggering a second time. The mob was low on hp and was trying to get away, but also had the second PC in grapple and wanted to drop him in a lavapool.

everything by the books? we were wondering because of the high amount of dmg that cantrip produced in one turn.:smallfrown:

thx for ur help :smallsmile:
Yeah, everything is by the book, no worries. ;)


Depends on when your DM rules the first one to proc. Is it when the enemy begins his move, or when he actually leaves the space, or what?
I'd argue that it doesn't happen until he leaves the space, because until that point he hasn't actually moved. But that creates a problem.
The problem is that effects from the same spell do not stack. You have two different instances of the same spell going off at the same time from the same trigger. So by the RAW, only one of the BBs actually procs, and the second one potentially does nothing (again, dependent upon when your DM rules the first to proc).
Except that this would be a clear houserule on your part.

Moving and leaving reach are two different things. Technically a creature could circle around another without getting an opportunity attack as long as it stays within 5 feet (although I don't see real-life examples of such a thing ^^).

Booming Blade does not say "take damage when leaving reach" but "take damage when willingly move", without any minimum distance required. So, right at the moment of the creature starts making a move (well, let's rather say "uses its movement speed" or "takes a single step/wing flap" to avoid ambiguity).

Opportunity attacks (which Warcaster replaces once the requirement is met) trigger "when a hostile creature that you can see moves out of your reach".
So at the right moment when the creature goes beyond a 5-feet distance cap.
Which necessarily means it already moved, as little as is.

So since "a movement" (which triggers BB) is required to create the state change "cross reach distance" (which triggers OA chance which triggers in turn Warcaster's BB), it's logical that Turn X's Booming Blade effect triggers before turn Y's Warcaster Booming Blade is applied.

[Citan]

This sounds wrong to me. It sounds like the cleric made an entirely new casting of Booming Blade as an opportunity attack. This is not allowed, you can only make a melee attack as an opportunity attack, not cast a spell. Booming blade is a spell cast that allows a melee attack as a part of it.

Two things would happen when the monster moves out of reach. When the monster willingly moves, Booming Blade will trigger, doing xd8 damage. Also, the cleric will be able to make a basic melee attack. Not cast another spell.
You are obviously not familiar with the Warcaster feat. :)

Confer PHB around page 170.

[Aett_Thorn]

This sounds wrong to me. It sounds like the cleric made an entirely new casting of Booming Blade as an opportunity attack. This is not allowed, you can only make a melee attack as an opportunity attack, not cast a spell. Booming blade is a spell cast that allows a melee attack as a part of it.

Two things would happen when the monster moves out of reach. When the monster willingly moves, Booming Blade will trigger, doing xd8 damage. Also, the cleric will be able to make a basic melee attack. Not cast another spell.

Not that he says that he has the Warcaster feat, which allows you to "When a hostile creature’s movement provokes an opportunity attack from you, you can use your reaction to cast a spell at the creature, rather than making an opportunity attack. The spell must have a casting time of 1 action and must target only that creature."

[DivisibleByZero]

Yeah, everything is by the book, no worries. ;)


Except that this would be a clear houserule on your part.

Moving and leaving reach are two different things. Technically a creature could circle around another without getting an opportunity attack as long as it stays within 5 feet (although I don't see real-life examples of such a thing ^^).

Booming Blade does not say "take damage when leaving reach" but "take damage when willingly move", without any minimum distance required. So, right at the moment of the creature starts making a move (well, let's rather say "uses its movement speed" or "takes a single step/wing flap" to avoid ambiguity).

Opportunity attacks (which Warcaster replaces once the requirement is met) trigger "when a hostile creature that you can see moves out of your reach".
So at the right moment when the creature goes beyond a 5-feet distance cap.
Which necessarily means it already moved, as little as is.

So since "a movement" (which triggers BB) is required to create the state change "cross reach distance" (which triggers OA chance which triggers in turn Warcaster's BB), it's logical that Turn X's Booming Blade effect triggers before turn Y's Warcaster Booming Blade is applied.

It isn't an houserule. It's a difference of when the DM decides that it procs. And you're nitpicking on my choice of particular wording when the intent of what I said is perfectly clear.

If you say that you're moving, and BB procs, and then you say "Well nevermind, I'll stay here" then it doesn't proc.
So a DM could (and IMO should) rule that it doesn't proc until you leave the square/space (because until that happens you haven't actually moved). At that point, the second one is invalid, because you have two instances of the same spell proc'ing off the same trigger, which is called stacking, and spell effects don't stack. So you could do it to get the initial damage, but the secondary damage wouldn't stack and therefore wouldn't proc.
No matter how you rule the RAW on this as to exactly when the movement triggers the BB, that is most definitely the RAI.

Initial damage on your turn from casting = Yes.
Secondary damage on the enemy's turn triggered by movement= Yes.
Initial damage from your WarCaster casting = Yes.
Secondary damage from WarCaster reaction, triggered by movement = No, because that would be stacking, and effects from the same spell do not stack.

[lebefrei]

You are obviously not familiar with the Warcaster feat. :)

Confer PHB around page 170.

Yeah I entirely missed that/didn't think about it, and I am familiar with it. Oops. That's what I get for posting before coffee.

[Citan]

It isn't an houserule. It's a difference of when the DM decides that it procs. And you're nitpicking on my choice of particular wording when the intent of what I said is perfectly clear.

If you say that you're moving, and BB procs, and then you say "Well nevermind, I'll stay here" then it doesn't proc.
Well, that's the wrong thing here that makes all your reasoning fall flat.
A creature cannot say "ok I move away" (DM "Booming Blade triggers as you move") then change opinion just for the sake of avoiding the effect.

You start moving > effect triggers immediately and instantly.

Because a reaction necessary happens AFTER its trigger, and that trigger was necessarily AFTER the start of movement (as little as may be required for you to leave the reach area and trigger OA>Warcaster), then is no stacking: when Warcaster's Booming Blade is cast, the previous Booming Blade already ended.

Your big problem is thinking with a squarred map in mind, that's why you cannot see how you are wrong. :)
Confer "So a DM could (and IMO should) rule that it doesn't proc until you leave the square/space (because until that happens you haven't actually moved)".
Magic is not so nice as to get a sentient mind to kindly count how many steps you took towards any direction before judging it's time to get active. XD
Just read the spell while putting aside all square reference and it will be clearer.


No matter how you rule the RAW on this as to exactly when the movement triggers the BB, that is most definitely the RAI.

Let's see a source then. :)

[DivisibleByZero]

Because a reaction necessary happens AFTER its trigger, and that trigger was necessarily AFTER the start of movement (as little as may be required for you to leave the reach area and trigger OA>Warcaster), then is no stacking: when Warcaster's Booming Blade is cast, the previous Booming Blade already ended.
Nope, you're the one that's wrong. Because an OA is one of the few reactions that interrupt, and doesn't wait for the trigger to finish.
If it did, the enemy would already be out of your reach and no longer eligible for an attack at all.
Because if the previous BB has already ended, then the enemy is already out of your reach and you can't BB them again.
In order for any of this to work, you have to stack the effects, which is not allowed.

So once again:
Initial BB damage: Yes
Secondary BB damage = Yes
Initial WC BB damage = Yes
Secondary WC BB damage = No, because that would be stacking.

Incidentally, this is precisely why I began my answer with the fact that it will depend on when your DM rules the first BB to take effect.
I'm now done debating this with you, because I answered your response before you even typed it.

[Provo]

Your big problem is thinking with a squarred map in mind

Well, this is a reasonable point. In theater of the mind, there clearly is no stacking issue.

That being said, if you play exclusively with a grid or hex map then then there is nothing wrong with making your ruleings with map structure in mind.

In this case I would allow it to proc twice. What if the creature moved to another threatened space before moving out the of your reach? (Examples: they are trying to get past you or you have a reach weapon) Then it would obviously proc twice. For consistency, I would have it act the same way in your situation.

[Contrast]

The problem is that effects from the same spell do not stack. You have two different instances of the same spell going off at the same time from the same trigger.

You interpretation of how the spell stacking rule works (i.e. one of the spells is ignored/neutered) seems problematic to me. For example, it becomes wildly unclear how two different people both hexing the same target would work. Does only one of them get the benefit? Does which ability gets disadvantage swap depending on who attacked last? PHB says the 'most potent - such as the highest bonus' takes precedence but in that case does that mean whoever its most optimals one is in effect or whoever has the better con save or casting stat or higher level spell slot used or...?

The way I see it the effects aren't really stacking (in that they don't take a single lot of thunder damage combined from both spells). They take two separate lots of damage. In the hex example, both people get the benefits of their hex individually and the guy gets both abilities reduced but he couldn't get 'double' disadvantage to one or take 2d6 extra damage.

This seems consistent with the wording and makes a lot more sense generally to me.

Edit - That said, having looked around, Sage Advice says no, you only get one (Link (https://www.sageadvice.eu/2015/11/27/if-a-creature-is-affected-by-3-booming-blades-does-effect-stack/))

[DivisibleByZero]

Edit - That said, having looked around, Sage Advice says no, you only get one (Link (https://www.sageadvice.eu/2015/11/27/if-a-creature-is-affected-by-3-booming-blades-does-effect-stack/))

Yep. There ya go.


So once again:
Initial BB damage: Yes
Secondary BB damage = Yes
Initial WC BB damage = Yes
Secondary WC BB damage = No, because that would be stacking.

As to the Hex example:


The way I see it the effects aren't really stacking (in that they don't take a single lot of thunder damage combined from both spells). They take two separate lots of damage. In the hex example, both people get the benefits of their hex individually and the guy gets both abilities reduced but he couldn't get 'double' disadvantage to one or take 2d6 extra damage.

C o m b i n i n g M a g i c a l E f f e c t s
The effects of different spells add together while the durations of those spells overlap. The effects of the same spell cast multiple times don't combine, however. Instead, the most potent effect—such as the highest bonus—from those castings applies while their durations overlap.

In your example, both spells would exist, but only one of them would be "active." The first one exists. The second one, when cast, would overwrite the first (as they were both of the same "potency"), and if a different Ability were chosen then the first Ability targeted would essentially pause.
If the second one were removed (concentration interrupted, dispelled, whatever), then the first would "unpause" and become active once again, assuming it were still being concentrated on and hadn't been dispelled or whatever.

So from a technical standpoint, for the BB example, the first one would get superceded by the second. But that's a moot point really, as regardless of which one is active, you only get the secondary damage once.
If they were from different casters of different levels, then the higher damage damage die pool would be the active one, regardless of the order they were applied to the target.

So technically, it would go like this:
Initial BB damage: Yes
Secondary BB damage = No (unless it were of an higher level with an higher damage dice pool).
Initial WC BB damage = Yes
Secondary WC BB damage = Yes (unless it were of a lower level with a lower damage dice pool, in which case the first Secondary damage would apply instead of this one).
Either way, the initial damage happens twice, once per casting. The secondary damage procs once, with the higher dice pool.

[Citan]

Nope, you're the one that's wrong. Because an OA is one of the few reactions that interrupt, and doesn't wait for the trigger to finish.
If it did, the enemy would already be out of your reach and no longer eligible for an attack at all.
Because if the previous BB has already ended, then the enemy is already out of your reach and you can't BB them again.
In order for any of this to work, you have to stack the effects, which is not allowed.

So once again:
Initial BB damage: Yes
Secondary BB damage = Yes
Initial WC BB damage = Yes
Secondary WC BB damage = No, because that would be stacking.

But no, you don't have.
You definitely don't have.
That's the big thing you just don't understand.

The fact that a creature may or not trigger an OA is irrelevant: as soon as it moves, it triggers BB effect, ending the spell. Whether you moved just one foot away, or several feet without leaving reach, or indeed moved enough feet to attain the reach limit which triggers the OA.

My turn: Action Booming Blade.
Enemy turn:
- starts moving > Booming Blade secondary damage IMMEDIATELY takes effect, ending the spell.
- gets at the reach limit > triggers OA > triggers Warcaster benefit.
- I make a successful Booming Blade.
- Enemy continues moving if he wishes to do so, triggering the secondary damage of the spell.

So there is NO stacking, just a succession of full spell effects, but none overlapping with each other.
Saying otherwise is tweaking the description of BB for the sake of your own sense of balance, which may or not be better I have no opinion on that, but certainly not RAW nor RAI until you get us an official quote of errata or twitter.
(The one from Contrast is useless, because the point of debate is the fact that we should consider both spell as stacking in the first place which is an entirely different question).

By the way...


Incidentally, this is precisely why I began my answer with the fact that it will depend on when your DM rules the first BB to take effect.
I'm now done debating this with you, because I answered your response before you even typed it.
Nice way to avoid a discussion you feel you are losing, but, you know the only reason I started this is because you presented things like there was any good reason to consider there were several ways to read this. And you are the first person I read on this forum who made such assertion on this topic, with some liberal reading of the book to create a premice that supports your choice.
If you just had told something like "not sure about RAW but in my games I rule like this for balance reason" then I would have rather asked you why you felt it unbalanced without discussing your choice. :)

[DivisibleByZero]

all that

Azuro @gandhi39
@JeremyECrawford Creature affected by 3 booming blades at the same time. When moving it takes damage 3 times?

Jeremy Crawford @JeremyECrawford
If a spell is cast multiple times on a target, the effects don't stack while the durations overlap (PH, 205). #DnD


Go argue it with JC. (https://www.sageadvice.eu/2015/11/27/if-a-creature-is-affected-by-3-booming-blades-does-effect-stack/)

[Aett_Thorn]

Yep. There ya go.



That link doesn't prove your point, at all. It's talking about three concurrent, not consecutive, applications of the same spell. If three PCs hit a target with three different Booming Blades, then only one is active at once, so the creature will only take damage once when it moves. That link says nothing about whether or not Booming Blade would happen BEFORE or AFTER an OA is provoked.

Creatures don't teleport in 5-foot segments. As soon as the creature STARTED to move, it would take the BB damage. Meaning that if it moved 1 foot, it would take the damage, and the spell would end. When it gets to 5 feet, and provokes an OA, then a second casting of BB could be done. There is not overlap here, as the first BB has already gone off before the second is applied.

[DivisibleByZero]

That link doesn't prove your point, at all.

Spell effects from the same spell do not stack.
If you want to argue it, argue with JC. The link to do so is right there.

[Aett_Thorn]

Spell effects from the same spell do not stack.
If you want to argue it, argue with JC. The link to do so is right there.

ONLY IF THEY OVERLAP. In the case of the OP, there is no point where the spells are overlapping.

"If a spell is cast multiple times on a target, the effects don't stack while the durations overlap"

[ThePolarBear]

Nope, you're the one that's wrong. Because an OA is one of the few reactions that interrupt, and doesn't wait for the trigger to finish.

Let's see the 2 cases:

Grid:
It doesn't exist a movement that can be less than the least unit: the square. You move in square (usually 5ft) increments.
When a creature moves to leave a square, it moves 5ft. It triggers both Booming blade and an AoO. The attack of opportunity triggers when the creature moves out of your reach (when the move is done) but happens just before the creature leaves but has already moved.
Booming blade should have already procced since it triggers immediately as the creature moves, which happens before the creature leaves.

ToTM:
Same as above, without the restrictions of being on a grid.

Booming Blade has no lower limit of how much you have to move, just that you have moved at all. It doesn't matter if you can also AoO because to cause an AoO the creature has already moved, thus triggered BB.

Also note that Warcaster does not, as written, allow the interruption of a move. So unless using a weapon with reach, the whole situation is absolutely not important since the attack cannot land in the first place.

[Citan]

Azuro @gandhi39
@JeremyECrawford Creature affected by 3 booming blades at the same time. When moving it takes damage 3 times?

Jeremy Crawford @JeremyECrawford
If a spell is cast multiple times on a target, the effects don't stack while the durations overlap (PH, 205). #DnD


Go argue it with JC. (https://www.sageadvice.eu/2015/11/27/if-a-creature-is-affected-by-3-booming-blades-does-effect-stack/)
See? As usual, you try to kick the ball clear when things don't go your way, although I anticipated this in my post by stressing that the tweet you shield behind does not serve the discussion.

Let's try again: question is not "do effects of stacked BB apply both" (we all already know the answer to that, and don't argue against it either).
Question is: "when enemy under BB moves to leave another creature's reach, is BB effect triggering before potential OA?"
Yes > no stack.
No > stack.
Simple enough.


Spell effects from the same spell do not stack.
If you want to argue it, argue with JC. The link to do so is right there.
Beware, you are losing it. ;)


ONLY IF THEY OVERLAP. In the case of the OP, there is no point where the spells are overlapping.

"If a spell is cast multiple times on a target, the effects don't stack while the durations overlap"
Indeed, seems DBZ needed the clarification.
Otherwise, it would be the same to say you cannot get healed by Healing Words more than once per round because it's the same spell effect. XD

[RickAllison]

I would point out that even when using spaces, you can move less than 5 feet in increments. The squares are reference lines and the vast majority of the time, we are concerned with them as base increments, but nothing prevents you from moving 2.5 feet, and it would not be uncalled-for to have a speed with only partial movement through a space. Halflings and dwarfs moving through difficult terrain can move two and a half squares, and you can bet there are times where I will vehemently defend my ability to take that little bit of extra movement because it adds up with time. Half-squares also come into play with Tiny creatures. You can even get weirder numbers, such as an enemy crawling through difficult terrain under spirit guardians. Per the PHB, "Crawling 1 foot in difficult terrain, therefore, costs 3 feet of movement." This is because you have two effects that cause the creature's movement to require 1 extra foot of movement per foot, and then the base speed would be halved by Spirit Guardians. A dwarf in the situation would only move 4.17 feet with his movement, or 6.25 if not crawling.

Put simply, the squares are only there for easy referencing. You certainly can move 4 feet before you leave the Booming Blade-caster's reach and would trigger the first spell, and it is very possible to only have that much movement. Note that this is different from moving within the creature's "square". If the caster is in square A3 and the enemy is in B3, the enemy could be moving around within B3 because his "square" happens to coincide with the boundaries of the grid square. He could move 2.5 feet south and then his "square" would be half in B3 and half in C3. Notably, he could do this to allow Tiny companions of his to get reach to the caster to attack without triggering an opportunity attack. The difference between this and moving around in the square is that it permanently shifts the controlled area and sets new bounds for where the enemy can move within the square. He might momentarily step "out" of reach of the caster, but he is still bound to the square and the caster can still strike him.

As a complete sidenote because i just re-read the "touch" range, Bugbears have the unique qualifier that they should be able to cast touch spells at 10 feet because that is the range that they can physically touch thanks to their Long-Limbed trait. This is probably pointless most of the time since most offensive touch spells also require an attack roll, but it does mean that a Long Death Monk can use its capstone at 10 ft and a bugbear PC can Cure Wounds an ally without necessarily entering a threatened space. Not relevant to the discussion here, but a fun little thing.

[DivisibleByZero]

The rules are clear.
If you guys want to argue it, argue it with JC, because the two of us are in agreement about the rules. You guys can try to warp reality all you want to and claim that both JC and I are wrong, but until and unless you confront him with this so that he can set you straight, I don't know what else to tell you.

[Aett_Thorn]

The rules are clear.
If you guys want to argue it, argue it with JC, because the two of us are in agreement about the rules. You guys can try to warp reality all you want to and claim that both JC and I are wrong, but until and unless you confront him with this so that he can set you straight, I don't know what else to tell you.

JC isn't talking about what you're talking about. So you're not in agreement.

JC is talking about what would happen if something like three players all hit the same target with Booming Blade on the same round, and then the creature moved. It would only take the damage once, because the spells are overlapping. He is NOT talking about what would happen if a creature moved, prompting a BB damage burst, and then provoked an OA of another BB.

You are extrapolating an answer that is not there.

[DivisibleByZero]

First sentence of the first response of this thread.


Depends on when your DM rules the first one to proc.

RAW is that it only happens once, because it doesn't stack.
If your DM rules that some shenanigans happen because they feel that the timing is important, they may rule that both apply.
The rules and the lead designer of the game,. who also happens to be the rules guru, disagree and claim that they don't stack.
Your DM may rule otherwise, as we are seeing.

[ThePolarBear]

I would point out that even when using spaces, you can move less than 5 feet in increments. The squares are reference lines and the vast majority of the time, we are concerned with them as base increments, but nothing prevents you from moving 2.5 feet, and it would not be uncalled-for to have a speed with only partial movement through a space. Halflings and dwarfs moving through difficult terrain can move two and a half squares, and you can bet there are times where I will vehemently defend my ability to take that little bit of extra movement because it adds up with time. Half-squares also come into play with Tiny creatures. You can even get weirder numbers, such as an enemy crawling through difficult terrain under spirit guardians. Per the PHB, "Crawling 1 foot in difficult terrain, therefore, costs 3 feet of movement." This is because you have two effects that cause the creature's movement to require 1 extra foot of movement per foot, and then the base speed would be halved by Spirit Guardians. A dwarf in the situation would only move 4.17 feet with his movement, or 6.25 if not crawling.

Put simply, the squares are only there for easy referencing. You certainly can move 4 feet before you leave the Booming Blade-caster's reach and would trigger the first spell, and it is very possible to only have that much movement. Note that this is different from moving within the creature's "square". If the caster is in square A3 and the enemy is in B3, the enemy could be moving around within B3 because his "square" happens to coincide with the boundaries of the grid square. He could move 2.5 feet south and then his "square" would be half in B3 and half in C3. Notably, he could do this to allow Tiny companions of his to get reach to the caster to attack without triggering an opportunity attack. The difference between this and moving around in the square is that it permanently shifts the controlled area and sets new bounds for where the enemy can move within the square. He might momentarily step "out" of reach of the caster, but he is still bound to the square and the caster can still strike him.

As a complete sidenote because i just re-read the "touch" range, Bugbears have the unique qualifier that they should be able to cast touch spells at 10 feet because that is the range that they can physically touch thanks to their Long-Limbed trait. This is probably pointless most of the time since most offensive touch spells also require an attack roll, but it does mean that a Long Death Monk can use its capstone at 10 ft and a bugbear PC can Cure Wounds an ally without necessarily entering a threatened space. Not relevant to the discussion here, but a fun little thing.

Rule wise, no, you can't. If you use a grid, the minimum distance is the distance of a square. Otherwise you are not considered to be "moving". During combat your speed becomes "x squares".

I mean, anyone can play the game as wanted, but PHB page 192 is what i mean.

Half squares as always are dropped (rules for difficult terrain).

You can defend your ability as much as you want, yell at the book as much as you want, but unless you spit so much while yelling that the pages become wet enough what is written is not going to change.

And again, to each their own since fun is what for your group is fun.

[Aett_Thorn]

First sentence of the first response of this thread.



RAW is that it only happens once, because it doesn't stack.
If your DM rules that some shenanigans happen because they feel that the timing is important, they may rule that both apply.
The rules and the lead designer of the game,. who also happens to be the rules guru, disagree and claim that they don't stack.
Your DM may rule otherwise, as we are seeing.

So you're basically saying that it's up to DM interpretation, AND that you're correct by RAW all at the same time?

Again, the JC quote that you are referring to is talking about a completely different situation, so I don't know why you keep using that as some sort of evidence.

Yes, this comes down to when the first Booming Blade goes off versus when the OA would apply. You are saying that YOU would rule it one way, but that doesn't make it RAW. IF you rule it the way you do, then you're right that it wouldn't stack. But that doesn't make your interpretation RAW or even RAI.


The part of BB that we're talking about comes down to this: "If the target willingly moves before then, it immediately takes 1d8 thunder damage, and the spell ends."

I would argue that a creature moving 5 feet would have FIRST had to have moved even a single foot, which would immediately cause this spell to discharge and the spell ends. This means that then the creature LEAVES the reach of the character, which prompts an OA, and War Caster allows for a new BB to be applied. If the creature kept moving, they'd take more damage. At no point in this movement are the two castings of the spell overlapping.

[DivisibleByZero]

So you're basically saying that it's up to DM interpretation, AND that you're correct by RAW all at the same time?

It's only up to DM interpretation insofar as everything is always open to DM Fiat/Rulings.
The rules are clear, they don't stack.
Any DM is welcome to override the rules for their own game, as always. As you apparently prefer to do, even if you aren't willing to acknowledge this is what you're doing.

[Lombra]

First sentence of the first response of this thread.



RAW is that it only happens once, because it doesn't stack.
If your DM rules that some shenanigans happen because they feel that the timing is important, they may rule that both apply.
The rules and the lead designer of the game,. who also happens to be the rules guru, disagree and claim that they don't stack.
Your DM may rule otherwise, as we are seeing.

Please read it all and don't be dismissive, DBZ.

You do not have the answer to the question. The question is wether BB can trigger two times in a round, not if BB can stack. Much like Sneak Attack is limited to once per turn, it can happen twice with reaction attacks.

The problem that I see is how one interpretates movement. We have feet as unit, but most reaches are 5ft, which means that, within the general approximation of the game, movements of 1ft can be performed. If 1ft movements can be performed, then you can move less than 5 feet, moving less than 5 feet, does not provoke OAs, because you are not leaving the reach of the enemy.

Since the trigger of BB is the willful movement of the target, and movements can be of less than 5 feet, it means that the trigger of BB can and will happen before any OA trigger, since, in order to perform an OA, the target must be leaving your reach.

But I see your point. And your point is that OAs happen before the target leaves your reach, if this weren't the case, OAs wouldn't be able to connect. You picture the OA as happening when the target drops the guard to move away, although, the PHB says that the OA happens right before the target leaves the threatened area, implying that the target has to move before being in such position. The OA interrupts the movement, but it can't interrupt it before it even starts, there isn't a stack zone like M:tG.

But yours is a fine houserule, and I actually like it more than how the actual rules make it work.

[Provo]

The rules and the lead designer of the game,. who also happens to be the rules guru, disagree and claim that they don't stack.

I don't think anybody on this thread has claimed that they stack...

Rather the argument seems to be that the OA hits AFTER the first booming blade is fully resolved

JC is clearly not talking about this issue. Everybody is in agreement that if the OA comes first, there will be only one instance of secondary damage.

[Citan]

Yes, this comes down to when the first Booming Blade goes off versus when the OA would apply. You are saying that YOU would rule it one way, but that doesn't make it RAW. IF you rule it the way you do, then you're right that it wouldn't stack. But that doesn't make your interpretation RAW or even RAI.


The part of BB that we're talking about comes down to this: "If the target willingly moves before then, it immediately takes 1d8 thunder damage, and the spell ends."

I would argue that a creature moving 5 feet would have FIRST had to have moved even a single foot, which would immediately cause this spell to discharge and the spell ends. This means that then the creature LEAVES the reach of the character, which prompts an OA, and War Caster allows for a new BB to be applied. If the creature kept moving, they'd take more damage. At no point in this movement are the two castings of the spell overlapping.


It's only up to DM interpretation insofar as everything is always open to DM Fiat/Rulings.
The rules are clear, they don't stack.
Any DM is welcome to override the rules for their own game, as always. As you apparently prefer to do, even if you aren't willing to acknowledge this is what you're doing.
Wow, typical DBZ. Someone is putting the exact PHB words in front of him, explaining it even, to try and make him understand why his view is at the very least debatable because the spell description itself is strongly gearing towards "successive separated spell instances" instead of "instances overlapped in the same timeframe"...

Then you DBZ look away "hey, my way is the RAW way I'm sure of it in spite of not following literal English, but you are free to do as you please in your games".

Face reality, don't worry it's not that bad.
Unless you really have trouble understanding the meaning of "immediately" and "the spell ends"? :)

[Aett_Thorn]

It's only up to DM interpretation insofar as everything is always open to DM Fiat/Rulings.
The rules are clear, they don't stack.
Any DM is welcome to override the rules for their own game, as always. As you apparently prefer to do, even if you aren't willing to acknowledge this is what you're doing.

Sigh...not what I'm doing at all. Because you haven't shown that the "rules are clear" on this. At least not favoring your side.

C...T...ES1...ES2

C= Caster
T= Target
ES1/2 = Empty Space 1/2

Each is a different 5' square on a grid.

Round 1: T goes first, and grapples the buddy of C, then C hits T with BB. We're all clear on that so far.

Round 2: T tries to get away from C, while dragging C's buddy away. He moves to ES1, which is 5' of movement


Now, you're saying that the OA from War Caster happens BEFORE the effects of BB go off. However, that is not necessarily RAW, it's just DM interpretation. However, based on the wording of BB, I would say that it happens IMMEDIATELY when the creature moves, meaning before he even gets to ES1. He had to have moved to get to move into space ES1, which prompts the OA in the first place. Thus, BB goes off and T moves into ES1, prompting a War Caster OA of another BB. T then continues moving into ES2, which would prompt the second BB to go off.


Now, if you can show me where RAW says that War Caster OA would happen BEFORE the actual move occurs, then you have a point. Until then, you're arguing that your RAI is RAW.

[DivisibleByZero]

You do not have the answer to the question. The question is wether BB can trigger two times in a round, not if BB can stack. Much like Sneak Attack is limited to once per turn, it can happen twice with reaction attacks.

Sneak attack being allowed a second time, on someone else's turn, has nothing to do with this.

Q: How many times is the target moving?
A: One.
Therefore, anything which procs off of movement can only happen once, as the target is only moving once, regardless of the distance moved. One move = one proc due to movement. Multiple procs = stacking.
It's not: "He moved an inch, and so this one procs, and then he kept moving, and so this second one procs."
He moved once, one procs. More than that is stacking.

[Finlam]

I would argue that a creature moving 5 feet would have FIRST had to have moved even a single foot, which would immediately cause this spell to discharge and the spell ends.

So if a character moves 1 inch or 1/2 of an inch or 1/1000 of an inch, it also triggers Booming Blade Damage? It seems a bit silly to imagine characters standing perfectly still as if petrified, yet somehow still able to make melee attacks against people next to them without triggering the Booming Blade damage.

But maybe in some theaters of the mind characters move only their arms in the most minimalistic and efficient fashion when attacking so as not to cause their feet to move at all? Or maybe they are stone-still petrified so as not to move at all and have learned to wield their weapons with their mind for the duration of the spell?

I think it makes more sense to interpret movement in the context that the game assumes i.e. the 5 ft square, otherwise the results are just plain silly.

[RickAllison]

Rule wise, no, you can't. If you use a grid, the minimum distance is the distance of a square. Otherwise you are not considered to be "moving". During combat your speed becomes "x squares".

I mean, anyone can play the game as wanted, but PHB page 192 is what i mean.

Half squares as always are dropped (rules for difficult terrain).

You can defend your ability as much as you want, yell at the book as much as you want, but unless you spit so much while yelling that the pages become wet enough what is written is not going to change.

And again, to each their own since fun is what for your group is fun.

Note that the rule you cited was a variant. It isn't just using a grid, it is actually adopting a change in the rules, and can be assumed as much as we would assume they are using variant encumbrance or longer rests. And it has weird implications of its own, such as creatures with enough modifiers like difficult terrain being fully unable to move, and anything to do with tiny creatures.

So unless the OP comes in and says they are using the variant rules, it is fair to say that they aren't in play. Variant rules in 5e are defined by functioning differently than the base system. Note that this is different than feats or multiclassing, which require DM permission to use but aren't actually variant rules. This is because they add additional options, but they don't actually change the rules. The rules are the same whether you can multiclass or take feats, but movement simply works differently if you use the grid variant.

So RAW, Booming Blade triggers when you move your space and thus the Warcaster Booming Blade would be separate. If the variant rule is used instead of the normal rules, then the second Booming Blade would not get the secondary damage possibly triggering. This is not because of the rules working like that, but because the variant functions that way.

[Lombra]

So if a character moves 1 inch or 1/2 of an inch or 1/1000 of an inch, it also triggers Booming Blade Damage? It seems a bit silly to imagine characters standing perfectly still as if petrified, yet somehow still able to make melee attacks against people next to them without triggering the Booming Blade damage.

But maybe in some theaters of the mind characters move only their arms in the most minimalistic and efficient fashion when attacking so as not to cause their feet to move at all? Or maybe they are stone-still petrified so as not to move at all and have learned to wield their weapons with their mind for the duration of the spell?

I think it makes more sense to interpret movement in the context that the game assumes i.e. the 5 ft square, otherwise the results are just plain silly.

I agree, but the conclusion is not RAW, because the space unit for movement is feet, not squares. Personally, I'd rule it at 5ft movement segments too, for simplicity's sake.

The more I look at BB the more I don't like it. It's a bad combination of flavor and mechanics IMO.

[Aett_Thorn]

So if a character moves 1 inch or 1/2 of an inch or 1/1000 of an inch, it also triggers Booming Blade Damage? It seems a bit silly to imagine characters standing perfectly still as if petrified, yet somehow still able to make melee attacks against people next to them without triggering the Booming Blade damage.

But maybe in some theaters of the mind characters move only their arms in the most minimalistic and efficient fashion when attacking so as not to cause their feet to move at all? Or maybe they are stone-still petrified so as not to move at all and have learned to wield their weapons with their mind for the duration of the spell?

I think it makes more sense to interpret movement in the context that the game assumes i.e. the 5 ft square, otherwise the results are just plain silly.

Even if you assume the 5-foot square, we're still good here. The target is moving out of one square, and into another, taking BB damage immediately. This move also triggers an OA from War Caster, landing a second BB. The target then moves yet another 5 feet, triggering the second burst of damage.

They're not getting two burst of damage from the same 5' movement, but two 5' movements that occur back to back.

Basically, we're arguing for an order of operations that isn't in the RAW. However, given the wording of the spell, and the logic of how characters would need to traverse even a grid, I'm fairly confident that the BB would happen first, then the move to the next square occurs, which would trigger the OA. Then the target can either stay there (and not take the second BB damage), or they can continue moving (and take the second BB damage).

[Citan]

But I see your point. And your point is that OAs happen before the target leaves your reach, if this weren't the case, OAs wouldn't be able to connect. You picture the OA as happening when the target drops the guard to move away, although, the PHB says that the OA happens right before the target leaves the threatened area, implying that the target has to move before being in such position. The OA interrupts the movement, but it can't interrupt it before it even starts, there isn't a stack zone like M:tG.

But yours is a fine houserule, and I actually like it more than how the actual rules make it work.
I understand his point as well, but I don't follow why he and you would deem this houserule necessary.

I mean, whether the player took the feat as a Variant Human or in an ASI later, it is still an investment. Also, since nothing prevents AFAIK a creature hit by an opportunity attack to change its mind and stop moving after that, it makes it a double-edge sword: if because of this, the creature would probably die right now because of Warcaster BB, then it would probably instead stick and attack you.

Also, in any fair and reasonable game, this would certainly be a sustainable tactic for a good while...
But then, once the adventurer group becomes famous from their exploits, or if they are fighting a big faction, words of this will be propagated everywhere and creatures will develop counter-measures (at the very least, "avoid melee" or "Disengage" or "only high AC engage" or "thunder-resistant engage").
Then the player would have to spend even more resources to overcome those (Sentinel to negate Disengage, Elemental Adept to overcome resistance)...

And if this would be a problem balance-wise, what to say about all those Sorcerers that multiclassed for armor that can Quicken or Twin Booming Blade? Sure, it's not exactly the same because it cost them resources on the fly (instead of the one-time investment of Warcaster), and it affect different targets, but some could argue that it is in fact even greater in power. :)

I really have trouble seeing where the balance problem is?

So if a character moves 1 inch or 1/2 of an inch or 1/1000 of an inch, it also triggers Booming Blade Damage? It seems a bit silly to imagine characters standing perfectly still as if petrified, yet somehow still able to make melee attacks against people next to them without triggering the Booming Blade damage.

If we really wanted to take the spell description literally, without PHB context, actually just breathing or moving an arm would be enough. XD (because "you move" is so broad in general).

In PHB context, in which move has a specific meaning of "significantly changing the whole body coordinates from x1y1z1 to x2y2z2 somewhere in a 3d space", and in which such coordinate changes is represented through a precise referential based on feet, the plain meaning becomes "as soon as you willingly start using your movement speed secondary damage takes effect and spell ends".
So obviously making weapon attacks wouldn't apply because you don't change your tactical position, as well as casting a spell.
If however you just decided to move 2 feet away towards a tree to get cover against a ranged guy for example, there is no reason why BB wouldn't trigger. ;)

[RickAllison]

So if a character moves 1 inch or 1/2 of an inch or 1/1000 of an inch, it also triggers Booming Blade Damage? It seems a bit silly to imagine characters standing perfectly still as if petrified, yet somehow still able to make melee attacks against people next to them without triggering the Booming Blade damage.

But maybe in some theaters of the mind characters move only their arms in the most minimalistic and efficient fashion when attacking so as not to cause their feet to move at all? Or maybe they are stone-still petrified so as not to move at all and have learned to wield their weapons with their mind for the duration of the spell?

I think it makes more sense to interpret movement in the context that the game assumes i.e. the 5 ft square, otherwise the results are just plain silly.

The discrepancy you are thinking of has to do with the weird way that BB works. "Movement" in 5e terms is not shifting around in your controlled space, but moving your controlled space. A bard or Bladesinger can freely dance around their square without using any movement because they haven't moved their ability to actually do anything. Movement only occurs when they reposition so that they control a new area. So it isn't that BB prevents you from moving in your square. You might be stumbling around, trying not to upset the delicate film of magic around you. However, extending yourself out to move your controlled area is enough to rupture it.

As for why it doesn't rupture when you swing a sword... magic?

[Lombra]

Sneak attack being allowed a second time, on someone else's turn, has nothing to do with this.

Q: How many times is the target moving?
A: One.
Therefore, anything which procs off of movement can only happen once, as the target is only moving once, regardless of the distance moved. One move = one proc due to movement. Multiple procs = stacking.
It's not: "He moved an inch, and so this one procs, and then he kept moving, and so this second one procs."
He moved once, one procs. More than that is stacking.

Oh I see. So if a target satisfies more than once the trigger of a spell, it can't be affected by that spell more than once? Even if the conditions are met without overlapping, and there's a separate cast for each trigger? It doesn't sound right, or RAW, plus, if this were the case, you wouldn't be able to cast a second BB as a reaction, which defies your previous statements.

[Dudewithknives]

This does not seem very complicate to me:

1. Player A casts booming blade and hits Mob A. Setting up the booming blade effect.
2. Player A's turn end, it is now Mob A's turn
3. Mob decides to move and moves away from player A.
4. The effect of the booming blade that Player A set up activates, does its damage and ends.
5. Mob A's has left the threatened area of Player A.
6. Player A gets to spend a reaction to take an opportunity attack, but they have war caster, so they can use a cantrip instead.
7. Player A casts booming blade and hits again.
8. The first booming blade has been applied and ended already so now the second booming blade is set up.
9. Mob A continues moves out of the threaded range and triggers the second booming blade effect.

Seems pretty straight forward.

[Aett_Thorn]

This does not seem very complicate to me:

1. Player A casts booming blade and hits Mob A. Setting up the booming blade effect.
2. Player A's turn end, it is now Mob A's turn
3. Mob decides to move and moves away from player A.
4. The effect of the booming blade that Player A set up activates, does its damage and ends.
5. Mob A's has left the threatened area of Player A.
6. Player A gets to spend a reaction to take an opportunity attack, but they have war caster, so they can use a cantrip instead.
7. Player A casts booming blade and hits again.
8. The first booming blade has been applied and ended already so now the second booming blade is set up.
9. Mob A continues moves out of the threaded range and triggers the second booming blade effect.

Seems pretty straight forward.

You would think.

[Lombra]

I understand his point as well, but I don't follow why he and you would deem this houserule necessary.

I mean, whether the player took the feat as a Variant Human or in an ASI later, it is still an investment. Also, since nothing prevents AFAIK a creature hit by an opportunity attack to change its mind and stop moving after that, it makes it a double-edge sword: if because of this, the creature would probably die right now because of Warcaster BB, then it would probably instead stick and attack you.

Also, in any fair and reasonable game, this would certainly be a sustainable tactic for a good while...
But then, once the adventurer group becomes famous from their exploits, or if they are fighting a big faction, words of this will be propagated everywhere and creatures will develop counter-measures (at the very least, "avoid melee" or "Disengage" or "only high AC engage" or "thunder-resistant engage").
Then the player would have to spend even more resources to overcome those (Sentinel to negate Disengage, Elemental Adept to overcome resistance)...

And if this would be a problem balance-wise, what to say about all those Sorcerers that multiclassed for armor that can Quicken or Twin Booming Blade? Sure, it's not exactly the same because it cost them resources on the fly (instead of the one-time investment of Warcaster), and it affect different targets, but some could argue that it is in fact even greater in power. :)

I really have trouble seeing where the balance problem is?

If we really wanted to take the spell description literally, without PHB context, actually just breathing or moving an arm would be enough. XD (because "you move" is so broad in general).

In PHB context, in which move has a specific meaning of "significantly changing the whole body coordinates from x1y1z1 to x2y2z2 somewhere in a 3d space", and in which such coordinate changes is represented through a precise referential based on feet, the plain meaning becomes "as soon as you willingly start using your movement speed secondary damage takes effect and spell ends".
So obviously making weapon attacks wouldn't apply because you don't change your tactical position, as well as casting a spell.
If however you just decided to move 2 feet away towards a tree to get cover against a ranged guy for example, there is no reason why BB wouldn't trigger. ;)

Mine isn't a point of balance really, I just don't like how it works, it's perfectly balanced, OAs are rare and it's fine to make them juicy, I just dislike the spell.

[Dudewithknives]

Mine isn't a point of balance really, I just don't like how it works, it's perfectly balanced, OAs are rare and it's fine to make them juicy, I just dislike the spell.

Yeah, they took the concept of balance and chucked it out the window when they created Booming Blade and Green Flame Blade.

[ThePolarBear]

Note that the rule you cited was a variant. It isn't just using a grid, it is actually adopting a change in the rules, and can be assumed as much as we would assume they are using variant encumbrance or longer rests. And it has weird implications of its own, such as creatures with enough modifiers like difficult terrain being fully unable to move, and anything to do with tiny creatures.

So unless the OP comes in and says they are using the variant rules, it is fair to say that they aren't in play. Variant rules in 5e are defined by functioning differently than the base system. Note that this is different than feats or multiclassing, which require DM permission to use but aren't actually variant rules. This is because they add additional options, but they don't actually change the rules. The rules are the same whether you can multiclass or take feats, but movement simply works differently if you use the grid variant.

So RAW, Booming Blade triggers when you move your space and thus the Warcaster Booming Blade would be separate. If the variant rule is used instead of the normal rules, then the second Booming Blade would not get the secondary damage possibly triggering. This is not because of the rules working like that, but because the variant functions that way.

Grid rules are grid rules. The ones i used are the one in the PHB. If you use another variant, then it's on you (you might use the one that is mentioned using "free form miniature placing" like wargames or whatever).
I use the only rules that we all have equal access to: the ones on the PHB.

BB triggers on a move, not when someone moved. AoO triggers when someone has moved, thus the moving has ended.

If you read my comment:Warcaster doesn't even factor in this discussion since the attack from Warcaster would trigger AFTER the movement has ended since Warcaster does not give an AoO and does not specify that the reaction takes place interrupting the trigger. Warcaster reaction happens AFTER the trigger as ended as per rules to reaction, so the move ended ANYWAY.

This whole discussion about how Booming Blade stacks or not is irrelevant since it does never happen in this situation.

This is both on a grid and in the ToTM.

[RickAllison]

Grid rules are grid rules. The ones i used are the one in the PHB. If you use another variant, then it's on you (you might use the one that is mentioned using "free form miniature placing" like wargames or whatever).
I use the only rules that we all have equal access to: the ones on the PHB.

BB triggers on a move, not when someone moved. AoO triggers when someone has moved, thus the moving has ended.

If you read my comment:Warcaster doesn't even factor in this discussion since the attack from Warcaster would trigger AFTER the movement has ended since Warcaster does not give an AoO and does not specify that the reaction takes place interrupting the trigger. Warcaster reaction happens AFTER the trigger as ended as per rules to reaction, so the move ended ANYWAY.

This whole discussion about how Booming Blade stacks or not is irrelevant since it does never happen in this situation.

This is both on a grid and in the ToTM.

There is a heavy difference between using a grid to reference distances (like using the adventures) and changing to a variant rules system. Re-read page 192, it is clearly labeled as a variant rule, just like variant encumbrance.

[ThePolarBear]

There is a heavy difference between using a grid to reference distances (like using the adventures) and changing to a variant rules system. Re-read page 192, it is clearly labeled as a variant rule, just like variant encumbrance.

Which is outside the topic of the post, and should be handled on its own thread if you really wish to continue.

[Spiritchaser]

I understand his point as well, but I don't follow why he and you would deem this houserule necessary.



Just dug through this thread.

I’d agree that by the letter of the law, the logic looks pretty clear.

The target must move before a reaction attack can occur, booming blade goes off when they move.
The booming blade must have gone off before the second instance was applied.
There is no stacking problem because the two durations never overlapped.
You get both procs.

But: I can see at least considering house ruling this.

A sorcerer with a “cooperative “ foe could pump out a lot of melee damage. For the price of a quickened cantrip, you can go north of 100 damage.

Now: I don’t think I would houserule this, because this requires your foe to behave a certain way, it alerts anyone nearby, it does cost some resources, etc. But I don’t think it’s a no-brainer.

[DivisibleByZero]

This does not seem very complicate to me:

1. Player A casts booming blade and hits Mob A. Setting up the booming blade effect.
2. Player A's turn end, it is now Mob A's turn
3. Mob decides to move and moves away from player A.
4. The effect of the booming blade that Player A set up activates, does its damage and ends.
5. Mob A's has left the threatened area of Player A.
6. Player A gets to spend a reaction to take an opportunity attack, but they have war caster, so they can use a cantrip instead.
7. Player A casts booming blade and hits again.
8. The first booming blade has been applied and ended already so now the second booming blade is set up.
9. Mob A continues moves out of the threaded range and triggers the second booming blade effect.

Seems pretty straight forward.

Except that isn't what actually happens.
What happens is this:

1. Player A casts booming blade and hits Mob A. Setting up the booming blade effect.
2. Player A's turn end, it is now Mob A's turn
3. Mob decides to move and moves away from player A.
4. The effect of the booming blade that Player A set up activates, does its damage and ends.
Deciding to move doesn't trigger anything. Until you actually DO move 5', as far as the game is concerned you haven't moved yet.
5 4. Mob A's has left the threatened area of Player A.
6 5. Player A gets to spend a reaction to INTERRUPT the movement before it finishes (so he STILL hasn't moved yet as far as the game is concerned) and take an opportunity attack, but they have war caster, so they can use a cantrip instead.
7 6. Player A casts booming blade and hits again. The enemy now has two instances of BB on him.
7. The enemy finishes moving that 5' which he originally declared.
8. The first booming blade has been is now applied and ended already so now the second booming blade is set up and the second booming blade overwrites it. Because the same spell doesn't stack with itself.
9. Mob A continues moves out of the threaded range and triggers the second booming blade effect, and only the second one, because the first has been overwritten.

It is pretty straight forward.

[Dudewithknives]

Except that isn't what actually happens.
What happens is this:

1. Player A casts booming blade and hits Mob A. Setting up the booming blade effect.
2. Player A's turn end, it is now Mob A's turn
3. Mob decides to move and moves away from player A.
4. The effect of the booming blade that Player A set up activates, does its damage and ends.
Deciding to move doesn't trigger anything. Until you actually DO move 5', as far as the game is concerned you haven't moved yet.
5 4. Mob A's has left the threatened area of Player A.
6 5. Player A gets to spend a reaction to interrupt the movement before it finishes (so he still hasn't moved yet as far as the game is concerned) and take an opportunity attack, but they have war caster, so they can use a cantrip instead.
7 6. Player A casts booming blade and hits again.
7. The enemy finishes moving that 5' which he originally declared.
8. The first booming blade has been is now applied and ended already so now the second booming blade is set up and the second booming blade overwrites it. Because the same spell doesn't stack with itself.
9. Mob A continues moves out of the threaded range and triggers the second booming blade effect, and only the second one, because the first has been overwritten.

Seems pretty straight forward.

You did not bother reading what I wrote, again.

I said on part 4, that they decide to move, and then moves away.
Moving is the trigger for the first booming blade, no matter where they move to. Could even be to an adjacent square to the player for all that matters.
This triggers the effect of the first booming blade.
Only after they have moved at fully out of their threatened area does the attack of opportunity happen.
Then the second casting of booming blade triggers.
Moving out of their threatened area is the second trigger.

[Citan]

Grid rules are grid rules. The ones i used are the one in the PHB. If you use another variant, then it's on you (you might use the one that is mentioned using "free form miniature placing" like wargames or whatever).
I use the only rules that we all have equal access to: the ones on the PHB.

BB triggers on a move, not when someone moved. AoO triggers when someone has moved, thus the moving has ended.

If you read my comment:Warcaster doesn't even factor in this discussion since the attack from Warcaster would trigger AFTER the movement has ended since Warcaster does not give an AoO and does not specify that the reaction takes place interrupting the trigger. Warcaster reaction happens AFTER the trigger as ended as per rules to reaction, so the move ended ANYWAY.

This whole discussion about how Booming Blade stacks or not is irrelevant since it does never happen in this situation.

This is both on a grid and in the ToTM.
So is so wrong whatever way you look at this I don't even know where to start from.
Or maybe yes?

1. "Grid rules are grid rules": yeah, and those are a variant rule, which is clearly represented by the inclusion of the word "Variant:" in the title. Exactly like using spell points is also a variant rule, here for your comfort and creativity, but not one you are supposed to follow by default.

Nowhere in all the plain rules of PHB is said "you cannot move less than 5 feet (or rather less than a square)". Quite on the contrary, read, page 190: "On your turn, you can move a distance up to your speed. You can use as much or as little of your speed as you like on your turn, following the rules here".
Rules which strongly hint that the basic unbreakable unit is "1 feet".
Which is perfectly logical, since PHB encourages battlemap and theater of the mind equally. And unless you developed thelepathy (in which case, "please teach me right now Master"), would be hard to take hard-wired distances in collective imaginary using real-world ruler or tape. ;)

2. "BB triggers on the move, not when someone moved".
Trying to put some ambiguity where there isn't won't work: description of Booming Blade is crystal clear: "immediately". Like, whatever happens just after, you already took the damage once you decided moving and took the first step.
Which should also be obvious to people, although that clearly isn't.

3. "Warcaster does not give an AoO and does not specify that the reaction takes place interrupting the trigger. Warcaster reaction happens AFTER the trigger".
That's some pretty convoluted way to see this, but I see where you come from, so I'll try to guide you from there. ;)

Warcaster describes itself as allowing you, "when a hostile creature's movement provoke an opportunity attack from you, to cast a spell... rather than making an opportunity attack".
So the trigger is the exact same moment as with normal OA, you just replace the usual weapon attack with a spell.
There is absolutely no question of whether Warcaster "gives an AO" or not, it's already there!
Warcaster follows exactly the sames rules as normal OA as far as trigger is concerned.

However, you do raise a point here: since...
- You use a reaction to cast a spell that "must have a casting time of 1 action", and
- The part of OA relative to "interrupt movement" is written in the description of the OA itself, rather than its trigger...
Should we consider that...
a) Warcaster does not interrupt movement?
b) Warcaster's spell effect is resolved after a "duration of an action" (read 6 sec, so after the creature's turn ended) rather than "duration of a reaction" (read instant)?

If we just take strict reading without considering everything else there is in PHB, you could see argument both ways for a) and b) likewise.
As for a), I'd personally agree both ways, especially since I don't see any mechanical difference (since BB of previous turn ended already ;)).
As for b)... I think the logical thinking is still that it is all resolved during the "reaction time". Three reasons.

First: Warcaster description gives a "1 action casting time restriction" but does not say "you cast the spell normally". Plus, if you consider that "turns" are only an abstraction to manage things that actually all happen concurrently, if you said "so you take the full 6 seconds to cast this spell", then it would "eat into" your own next turn.

Second, let's consider the situations pre-SCAG: you already had melee cantrips and spells.
If you consider that Warcaster's spell would take the usual time to resolve, then all Shocking Grasp, Bestow Curse, Vampiric Touch and the like would create a logic fail because the target would be out of reach at the time (because it probably had some movement left after the OA trigger).

Three: beyond all that, well, the classic "specific trumps general": feat is a specific set of rules, so there is no reason why it couldn't bend the usual timing management. And the "1 action" limitation was obviously just a "spell choice restriction" set to keep coherence with the overall combat abstraction while allowing you to actually use a useful spell (considering so few "native reaction spells" exist, and how most of them are purely defensive).

Because of this, it seems obvious to me that OA Warcaster's timeframe is exactly the same as the "OA's normal weapon attack" timeframe.
So the Warcaster's Booming Blade weapon attack is made instantly, so "during" enemy movement.
Which means by your reading ("Warcaster does not interrupt movement" it's even worse because it would mean the creature continues on its initial decision to move, thus automatically triggering the new BB's effect.
Because of that, it's much more reasonable to really see Warcaster as just a plain substitution of "weapon attack" for "chosen spell effect" while keeping everything else the same (same trigger, same "movement interruption" -which is there mainly to give the creature a chance to react and a choice to change its mind afterwards-).

>>> However way you look at it, it "just works". ;)



Deciding to move doesn't trigger anything. Until you actually DO move 5', as far as the game is concerned you haven't moved yet.
Impressive. Now you clearly and completely goes against the literal letter of the PHB.
Reminders.

Movement
- "On your turn, you can move a distance up to your speed. You can use as much or as little of your speed during your turn, following the rules".
- Base unit of move is 1 feet, as illustrated by rules about crawling or difficult terrain ("every foot of difficult terrain costs 1 extra foot").
>>> You can move just 1 feet if you'd like. With the right (unlucky for you) set of conditions, you could even not be able to move 5 feet as illustrated by someone above.

Booming Blade
The target "becomes sheathed in booming energy until the start of your next turn. If the target willingly moves before then, it immediately takes 1d8 thunder damage, and the spell ends."
>>> Damage triggers either immediately when you start moving (ToTM, liberal) or on the first 1 feet spent (ToTM, gamist, or on battlemap with ruler). Exit the "5 feet minimum" nonsense.
(Otherwise, a friend with Sentinel hitting the same enemy would create circular logic: if the enemy ends up not moving because of that, with your "logic", the enemy would have in fact not moved at all, so then it would have not provoked the OA, so then it would still have move so it would move thus provoking the OA etc).

Opportunity Attacks
"You can make an opportunity attack when a hostile creature that you can see moves out of your reach".
Meaning you can make an OA when the creature changes state from "within reach" to "out of reach". Which in essence means you already spent some speed to move, otherwise such state change would not be happening. Which necessarily implies that BB effect happened before OA requirement is met, meaning that the BB of your turn has ended, whether you were gonna make a plain OA, a Sentinel OA or a Warcaster's OA.
Meaning that the BB effect you will apply as part as OA doesn't overlap since the previous went out of existence before.

I really cannot get why it's impossible for you to understand something as simple as that...

[Contrast]

For clarity I included the Sage Advice as it refuted the argument I specifically had made that I didn't really see the spells as stacking. I disagree with Sage Advice on how this should work but that's life I guess. I agree it says nothing about the potential trigger order of Booming Blade damage and opportunity attacks. I have no idea what is right in that case and am going to stay out of that argument :smalltongue:


In your example, both spells would exist, but only one of them would be "active." The first one exists. The second one, when cast, would overwrite the first (as they were both of the same "potency"), and if a different Ability were chosen then the first Ability targeted would essentially pause.
If the second one were removed (concentration interrupted, dispelled, whatever), then the first would "unpause" and become active once again, assuming it were still being concentrated on and hadn't been dispelled or whatever.

So from a technical standpoint, for the BB example, the first one would get superceded by the second. But that's a moot point really, as regardless of which one is active, you only get the secondary damage once.
If they were from different casters of different levels, then the higher damage damage die pool would be the active one, regardless of the order they were applied to the target.

So technically, it would go like this:
Initial BB damage: Yes
Secondary BB damage = No (unless it were of an higher level with an higher damage dice pool).
Initial WC BB damage = Yes
Secondary WC BB damage = Yes (unless it were of a lower level with a lower damage dice pool, in which case the first Secondary damage would apply instead of this one).
Either way, the initial damage happens twice, once per casting. The secondary damage procs once, with the higher dice pool.

On the basis of whats been laid out, lets say a level 20 character attacks first and gets their booming blade in place. Then a level 1 character attacks with Booming Blade.

If we're assuming they get to keep the more 'potent' one, based on the Sage Advice and combining rules, shouldn't the level 1 character not even get the initial bonus hit damage? The previous booming blade is still in its 'duration' after all. If you're trying to follow RAW I'm not sure I get the logic of allowing one part of the spell to function and not another.

Edit - Level 5 not 1 I guess seeing as they don't get any initial damage at level 1 :smalltongue:

[DivisibleByZero]

On the basis of whats been laid out, lets say a level 20 character attacks first and gets their booming blade in place. Then a level 1 character attacks with Booming Blade.

If we're assuming they get to keep the more 'potent' one, based on the Sage Advice and combining rules, shouldn't the level 1 character not even get the initial bonus hit damage? The previous booming blade is still in its 'duration' after all. If you're trying to follow RAW I'm not sure I get the logic of allowing one part of the spell to function and not another.

Edit - Level 5 not 1 I guess seeing as they don't get any initial damage at level 1 :smalltongue:

I would rule that the lower level (less potent) one would still get the initial damage.
The weapon attack and the initial thunder damage are instantaneous. The lingering effect is not.


On a hit, the target suffers the attack's normal effects, and it becomes sheathed in booming energy until the start of your next turn. If the target willingly moves before then, it immediately takes 1d8 thunder damage, and the spell ends.
This spell's damage increases when you reach higher levels. At 5th level, the melee attack deals an extra 1d8 thunder damage to the target, and the damage the target takes for moving increases to 2d8. Both damage rolls increase by 1d8 at 11th level and 17th level.

The attack's normal effects, plus an additional (variable) Xd8 thunder damage. You could negate the extra thunder damage if you really wanted to be mean, but I wouldn't.
My ruling would be that the initial attack is as per normal, as it is instantaneous. The lingering effect (that of being sheathed in booming energy, which breaks upon movement) is the part that can't stack, as it isn't instantaneous.

[ThePolarBear]

So is so wrong whatever way you look at this I don't even know where to start from.

From the beginning and from the rules as written.


1. "Grid rules are grid rules": yeah, and those are a variant rule, which is clearly represented by the inclusion of the word "Variant:" in the title. Exactly like using spell points is also a variant rule, here for your comfort and creativity, but not one you are supposed to follow by default.

The Default is ToTM. If you are using a grid:



VARIANT: PLAYING ON A GRID
If you play out a combat using a square grid and miniatures or other tokens, follow these rules.

It might have "Variant" in the name, but the intent is quite clear: If you are not using ToTM, you are using a variant. If you are using a grid, this are the rules.
If you are using a grid and not using this rules you are not following RAW. Which is fine, to anyone their own. But RAW is the thing we can discuss on by having all the same rules in front and start from there to give each their spin.

So, let's go ahead.


2. "BB triggers on the move, not when someone moved".
Trying to put some ambiguity where there isn't won't work: description of Booming Blade is crystal clear: "immediately". Like, whatever happens just after, you already took the damage once you decided moving and took the first step.
Which should also be obvious to people, although that clearly isn't.

It's obvious to me. As soon someone moves, BB triggers. In the ToTM it can be a one inch movement. On Grid, that's a 5' movement. However, as soon as that movement starts (and it clearly started before triggering the AoO) the damage is done. I'm not trying to argue otherwise

It simply also works the other way around: what matters is that it should trigger before the trigger for AoO, since the trigger for BB is that someone moves, while the one for AoO is "has moved outside".

One is something that has no limit: It is a simple action that has a mechanical implication inside the rules - there's a movement that is meant to change the position of a character in a way that might be meaningful for rules and that character has expended movement willingly.
The second requires that the moving has 1) reached a point where it came to a sort of end state, there's another condition checked, even if the movement itself has not ended 2) it is only equal to the first if there's the absolute minimum possible distance valid for BB to trigger between the afore mentioned condition changes "state". Which is so impossibly rare that's quite simply impossible and should be dismissed for sanity's sake if not for anything else.


3. "Warcaster does not give an AoO and does not specify that the reaction takes place interrupting the trigger. Warcaster reaction happens AFTER the trigger".
That's some pretty convoluted way to see this, but I see where you come from, so I'll try to guide you from there. ;)

Warcaster describes itself as allowing you, "when a hostile creature's movement provoke an opportunity attack from you, to cast a spell... rather than making an opportunity attack".
So the trigger is the exact same moment as with normal OA, you just replace the usual weapon attack with a spell.

No. It triggers in the exact same moment: When the creature has LEFT your reach. But it doesn't allow for the part where you attack just before the creature leaves because that's part of the reaction spent to make the AoO, not the reaction spent to cast the spell. You do not cast a spell insted of taking the AoO, you spend a reaction to cast a spell. You are not spending your reaction to take the AoO, even if the trigger is the same.


There is absolutely no question of whether Warcaster "gives an AO" or not, it's already there!

Yes. Warcaster does NOT give you an AoO. Basic rules give you when you can take an AoO - when the trigger happens. Warcaster does NOT change the trigger, does NOT change the AoO. It gives you the possibility to spend a reaction to do something different than making an AoO.


Warcaster follows exactly the sames rules as normal OA as far as trigger is concerned.

Yes. It's not the trigger that gives you the change in pacing of the reaction. That's the reaction. And you are not taking an AoO.


However, you do raise a point here: since...
- You use a reaction to cast a spell that "must have a casting time of 1 action", and
- The part of OA relative to "interrupt movement" is written in the description of the OA itself, rather than its trigger...

All reactions have their special timings, if present, in the description of the reaction itself, not in the trigger. The trigger is only a trigger. The timing is part of the reaction itself.


Should we consider that...
a) Warcaster does not interrupt movement?
b) Warcaster's spell effect is resolved after a "duration of an action" (read 6 sec, so after the creature's turn ended) rather than "duration of a reaction" (read instant)?

If we just take strict reading without considering everything else there is in PHB, you could see argument both ways for a) and b) likewise.

As for a), I'd personally agree both ways, especially since I don't see any mechanical difference (since BB of previous turn ended already ;)).
As for b)... I think the logical thinking is still that it is all resolved during the "reaction time". Three reasons.

First: Warcaster description gives a "1 action casting time restriction" but does not say "you cast the spell normally". Plus, if you consider that "turns" are only an abstraction to manage things that actually all happen concurrently, if you said "so you take the full 6 seconds to cast this spell", then it would "eat into" your own next turn.

Second, let's consider the situations pre-SCAG: you already had melee cantrips and spells.
If you consider that Warcaster's spell would take the usual time to resolve, then all Shocking Grasp, Bestow Curse, Vampiric Touch and the like would create a logic fail because the target would be out of reach at the time (because it probably had some movement left after the OA trigger).

Three: beyond all that, well, the classic "specific trumps general": feat is a specific set of rules, so there is no reason why it couldn't bend the usual timing management. And the "1 action" limitation was obviously just a "spell choice restriction" set to keep coherence with the overall combat abstraction while allowing you to actually use a useful spell (considering so few "native reaction spells" exist, and how most of them are purely defensive).

Because of this, it seems obvious to me that OA Warcaster's timeframe is exactly the same as the "OA's normal weapon attack" timeframe.

a) Warcaster does not stop movement. It's not Sentinel. It doesn't even interrupt movement as the reaction has no special timing attached, so it resolves as default: after the trigger. There's no argument here to be made.
b) I don't even. Warcaster doesn't give you an action. You can cast a spell with the casting time of an action and all other stull as a reaction. That's it.
An action spell does not take 6 seconds to cast. An Action does not take six seconds. An action takes a variable time frame. You are not using an action to begin with. Whatever casting time was the spell, it's now 1 reaction. There's no argument here too.
1) If the casting time was 6 seconds, it would say 6 seconds. It doesn't. It's an action.
2) Nothing ever said you could use spells with a 5' range with Warcaster. Warcaster doesn't interrupt the movement. Warcaster has no special timing. The trigger happens when a creature leaves. The reaction happens at default timing. If the target is in range, you can cast a spell. If it isn't you can't for normal rules for spellcasting. Warcaster doesn't make exceptions on range of the spell to be cast.
3) Because it doesn't is all the reason you need to believe that it doesn't. Specific > General. But there's no specific here.

Warcaster is NOT an AoO. It is EXPLICITLY NOT an AoO.


However way you look at it, it "just works". ;)

The only way you can make "it work" is if you are not looking at the rules for 5e, with the exception of BB+Warcaster+Spell Sniper+Reach weapon.
Then again, do whatever you want if it is fun for you.

[Mellack]

BB only triggers if you leave your square. Other movement, such as dodging and getting up from prone do not trigger it. Since I would think both of those are at least equivalent to move 1 foot, I cannot say such movement sets off BB. That same movement does not trigger an AoO. You have to leave your square to trigger either of those. Since AoO specifies that it happens before leaving, a single square of movement cannot trigger BB more than once, imo.

Now there is a way to make it work, the simplest being a reach weapon and spell sniper. The first square of movement triggers the spell but does not take them out of reach. The second square away triggers the AoO and can be used for another BB. This can also be done by forcing them to have to run past you to get away.

[Aett_Thorn]

BB only triggers if you leave your square.

Citation needed, please.

[Mellack]

Citation needed, please.

I explained it in the post. Smaller movements such as getting up from prone and dodging do not trigger it. Why would jumping in 2 feet on your dagger attack (still in your square) not trigger it but starting to move one foot (still in your square) will? It is an inference from the rules.

[Aett_Thorn]

I explained it in the post. Smaller movements such as getting up from prone and dodging do not trigger it. Why would jumping in 2 feet on your dagger attack (still in your square) not trigger it but starting to move one foot (still in your square) will? It is an inference from the rules.

Honestly, the way I take it is that "movement" is part of your character's turn. Anything that doesn't count as that kind of movement doesn't count as "movement". So attacking doesn't count. Standing up has been considered movement but not "movement" (it basically just drains "movement"). However, if a target/character that has been hit by BB states that they move one foot to the right (for some odd reason), I'd still say that BB goes off, since they say they are moving.

Nothing in the spell's description requires that the target move out of their square (and the "square" is a variant rule anyways, as discussed above).

[Mellack]

Would you have that same one foot move trigger an AoO? I feel if it is not enough to trigger one it is not enough to trigger the other.

[Aett_Thorn]

Would you have that same one foot move trigger an AoO? I feel if it is not enough to trigger one it is not enough to trigger the other.

No, because the AoO has a very specific timing of when it occurs, and that is when the creatures moves out of the reach of the enemy. So, for instance, if the enemy moves a foot away to grab an item off of the floor, that would trigger BB, but likely not an AoO. However, if the enemy and the player were right on the edge of each other's reach (somehow explicitly stated), then that foot of movement would trigger both, because both conditions have been met.

BB does not give a minimum amount of movement required to trigger it. AoOs do (you need to move out of reach). So something that triggers BB might not trigger an AoO. Same thing happens if you're using a reach weapon. If they move 5' (a square) away, then BB would go off, but the character wouldn't get an AoO, since the enemy is not moving out of their reach yet.

[Mellack]

Do you normally have your character position delineated down to that exact a distance? I have never seen that personally. All game measurements seem to be in 5 foot squares. I have never said if I am at the very front or back of the square. I would think in most events people are moving around in that square, especially during combat. But none of those movements trigger either BB or an AoO. Why would I ever need to say I am moving one foot. I have only ever seen moves done in 5 foot increments, so that is the minimum distance I would use to trigger either effect. I would anything less doesn't use up any of your move, so it doesn't count. I will say that I play on a grid so we only ever use 5' as a minimum.


Same thing happens if you're using a reach weapon. If they move 5' (a square) away, then BB would go off, but the character wouldn't get an AoO, since the enemy is not moving out of their reach yet.

This is true and I even used that example myself above. I think it is possible to do BB twice. I do not think the same 5' square of movement can trigger it twice.

[Kane0]

Blades generally don't have that effect when used for gardening.

[Contrast]

I would rule that the lower level (less potent) one would still get the initial damage.
The weapon attack and the initial thunder damage are instantaneous. The lingering effect is not.

I assume we agree RAW doesn't really make any comment on allowing some parts of a spell to trigger and not others. I don't see any RAW justification supporting the instantaneous bit.

Would you rule someone afflicted with 2 phantasmal forces sees a second creature appear (for an instant) but then it seems to vanish before it can attack?

Another example would be flaming sphere. If we rule this way, if someone is standing in the radius of a flaming sphere and then gets hit by another one, they take 2 sets of damage but if they stand in the radius of two they only take one set. Seems nonsensical to me.

I'm of the opinion that the rule was designed to stop buff/debuff stacking but was poorly worded. I agree that trying to haste a hasted person shouldn't work but making me able to see through Major Image because my friend with a higher spell DC cast another one on top of it seems...unintended. Or being able to cast Hypnotic Pattern on the party and instantly cancelling concentration to wake them all up from an opponents Hypnotic Pattern.

[Avonar]

I think the problem is that people are getting very hung up on moving an inch etc. This is designed for a grid, for players to move in 5ft increments. Personally I would say that an attack of opportunity is triggered when the enemy moves 5ft away. So, I think it would go like this:

Enemy moves away, suffers Booming Blade damage
Enemy triggers opportunity attack, Warcaster allows for Booming Blade again
Enemy is now 5ft away, under the effect of second Booming Blade
If enemy moves again, enemy takes second Booming Blade damage. If enemy choose not to move again, no damage.

I don't like the idea of triggering the BB damage twice off a single movement, as it is not designed for stopping halfway through a square. But I do think that the second Booming Blade would take effect, it would just take effect AFTER the first square of movement.

[Aett_Thorn]

I think the problem is that people are getting very hung up on moving an inch etc. This is designed for a grid, for players to move in 5ft increments. Personally I would say that an attack of opportunity is triggered when the enemy moves 5ft away. So, I think it would go like this:

Enemy moves away, suffers Booming Blade damage
Enemy triggers opportunity attack, Warcaster allows for Booming Blade again
Enemy is now 5ft away, under the effect of second Booming Blade
If enemy moves again, enemy takes second Booming Blade damage. If enemy choose not to move again, no damage.

I don't like the idea of triggering the BB damage twice off a single movement, as it is not designed for stopping halfway through a square. But I do think that the second Booming Blade would take effect, it would just take effect AFTER the first square of movement.

I don't think that anyone here is saying that a simple 5' movement would proc BB twice. Look at the OP, and you see that the target moved MORE than 5 feet on his turn. So he's moving more than 5', which is what allows BB to proc twice. Once when he makes the first move 5' and provokes the AoO (which causes a second casting of BB), and then BB again when he moves another 5 feet.

[Varlon]

Personally I would say that an attack of opportunity is triggered when the enemy moves 5ft away.

Here's the issue, which is that the PHB says that "The attack interrupts the provoking creature’s movement, occurring right before the creature leaves your reach". (They also need to be within 5 feet of you for you to be able to attack with most weapons anyway.) So they're still in the original square, or at least transitioning, when you make the OA. Those who are saying you can't apply BB twice are saying that the enemy only counts as having moved once they get to the next square, with movement being in discrete 5-foot chunks. Those who are saying you can apply it twice are saying that to move 5 feet you have to move 1/2/3/4 feet first, so the first BB will pop before you apply the second.

The "Playing on a Grid" section says "Rather than moving foot by foot, move square by square on the grid. This means you use your speed in 5-foot segments". It's possible to read this to mean that you couldn't apply BB twice, but it's also possible to read it as just saying that when you're keeping track of your remaining movement, that number is never going to be, say, 26.

I'm inclined to say you can apply it twice (though not popping twice on the same 5-foot movement) for two reasons:
1) To me it seems strange that what type of battle mat you play on could affect the mechanics of how a spell works. And it is extremely clear that the normal rule is for movement to be one foot at a time, given that "Playing on a Grid" says "Rather than moving foot by foot...".
2) But also, "The attack interrupts the provoking creature’s movement" seems to tell me that if they've reached the point where they've provoked an OA, they've already started moving.

[guachi]

This does not seem very complicate to me:

1. Player A casts booming blade and hits Mob A. Setting up the booming blade effect.
2. Player A's turn end, it is now Mob A's turn
3. Mob decides to move and moves away from player A.
4. The effect of the booming blade that Player A set up activates, does its damage and ends.
5. Mob A's has left the threatened area of Player A.
6. Player A gets to spend a reaction to take an opportunity attack, but they have war caster, so they can use a cantrip instead.
7. Player A casts booming blade and hits again.
8. The first booming blade has been applied and ended already so now the second booming blade is set up.
9. Mob A continues moves out of the threaded range and triggers the second booming blade effect.

Seems pretty straight forward.

The attack of opportunity happens before you actually leave reach, though. Your #6 is actually #4. Since it's actually step #4, you'll cast booming blade on a target that already has booming blade so the new casting does nothing.

Though given what the OP wrote, it's not the same as your scenario. The enemy moved around the PC, not away from the PC. Moved 5' (or 10' or 15') while still adjacent to the PC and triggers BB. Then moves away from the PC triggering warcaster while still 5' from the PC. If the enemy survives, he may move into an adjacent square.

[Varlon]

Though given what the OP wrote, it's not the same as your scenario. The enemy moved around the PC, not away from the PC. Moved 5' (or 10' or 15') while still adjacent to the PC and triggers BB. Then moves away from the PC triggering warcaster while still 5' from the PC. If the enemy survives, he may move into an adjacent square.

I would hope that what people have been arguing about more recently is whether you can reapply BB during the same 5-foot movement that pops the first instance of it. Because if not, there's no reason to talk about multiple instances and the question becomes a whole lot simpler: "does BB trigger instantly if you apply it as a replacement for an opportunity attack, or do they have to move another square?"

[Chugger]

The rules are clear.
If you guys want to argue it, argue it with JC, because the two of us are in agreement about the rules. You guys can try to warp reality all you want to and claim that both JC and I are wrong, but until and unless you confront him with this so that he can set you straight, I don't know what else to tell you.

This is pretty amazing. In all seriousness, to be this committed to your argument ... all I can say is, "Wow."

[Elric VIII]

I had always assumed that the first movement triggered BBs rider, then the AoO occurred, then they are in the new square 5ft away wit another BB rider to potentially trigger.


The creature mast have moved to trigger an AoO, therefore it would have also triggered an existing BB. The problem comes from resolving simultaneous actions in discreet steps.

Here's something to consider: I have a Warlock with Repelling Blast anf War Caster. An enemy leaves my threatened area and I use RB. How far away from me is it when my EB is done resolving? Did it consume 5ft worth of movement to end up 15ft away or does it have its full movement 10ft away.

I would say it is 15 feet away because it would have had to have moved for the AoO to come up at all. These things happen simultaneously in reality, but in the game you do them in steps. Begin moving, trigger BB, resolve AoO, finish moving, decide to continue or not.




This is pretty amazing. In all seriousness, to be this committed to your argument ... all I can say is, "Wow."

Am I the only one that sees the humor in a poster named DivisibleByZero being irrational?:smallconfused:

[Chugger]

Am I the only one that sees the humor in a poster named DivisibleByZero being irrational?:smallconfused:

That's an excellent observation.

And look, this is the Internet - so I'm going to try to be nice here. We can't know what real life issues other people have. Others might be very literal - might even have autism or an issue similar to it. It's normal for otherwise very smart people to get caught up or be "blind" to certain things. It's a big world and there's already enough pain going around. So I apologize if I was being snarky and really shouldn't have been.

A serious question: would I be banned from this forum if I were to seriously argue this topic from the standpoint of Zeno's paradoxes?! :smallbiggrin:

[DivisibleByZero]

The rules are clear.
If you guys want to argue it, argue it with JC, because the two of us are in agreement about the rules. You guys can try to warp reality all you want to and claim that both JC and I are wrong, but until and unless you confront him with this so that he can set you straight, I don't know what else to tell you.
This is pretty amazing. In all seriousness, to be this committed to your argument ... all I can say is, "Wow."

Am I the only one that sees the humor in a poster named DivisibleByZero being irrational?:smallconfused:
That's an excellent observation.

And look, this is the Internet - so I'm going to try to be nice here. We can't know what real life issues other people have. Others might be very literal - might even have autism or an issue similar to it. It's normal for otherwise very smart people to get caught up or be "blind" to certain things. It's a big world and there's already enough pain going around. So I apologize if I was being snarky and really shouldn't have been.

A serious question: would I be banned from this forum if I were to seriously argue this topic from the standpoint of Zeno's paradoxes?! :smallbiggrin:

You apologize for being snarky, and then in the same breath you imply that I have autism?
I'm done with you.

As for my being irrational: I'm not the one being irrational.
The lead designer and rules sage has answered the question. The rules support exactly the statement that he made. You guys are trying to do mental gymnastics claiming that he was answering a different question, but the fact is that he wasn't. He simply quoted the relevant rule. That rule is also relevant to the stacking question posed here. It's the same answer for the same rule, because it is in essence the same question, just worded differently. Even if it weren't the same question, which it essentially is, the rule is and would still be relevant. That rule states that the same spell doesn't stack with itself. Word the question any way that you want to, it gets the same answer. No stacking.
It absolutely is normal for otherwise very smart people to get caught up or be "blind" to certain things. That's exactly what you guys are doing by ignoring the fact that the question has been asked and answered, with that answer pointing to the relevant rule.
I'm not the one twisting the question and the answer because I don't like it. Therefore, I'm not the one being irrational.
You can rule however you like for your own game, but the RAW, the RAI, and the statements by the designer and rules guru all disagree with you. If you have a problem with that, don't personally attack me by implying that I might have autism, and instead just take it up with him.

[Citan]

You apologize for being snarky, and then in the same breath you imply that I have autism?
I'm done with you.

As for my being irrational: I'm not the one being irrational.
The lead designer and rules sage has answered the question. The rules support exactly the statement that he made. You guys are trying to do mental gymnastics claiming that he was answering a different question, but the fact is that he wasn't. He simply quoted the relevant rule. That rule is also relevant to the stacking question posed here. It's the same answer for the same rule, because it is in essence the same question, just worded differently.

It absolutely is normal for otherwise very smart people to get caught up or be "blind" to certain things. That's exactly what you guys are doing by ignoring the fact that the question has been asked and answered, with that answer pointing to the relevant rule.

And still he sticks to his "yeah it's the same thing" when everyone tried to explain to him it's not.

And then he sees the mote in his adversaries's eye, while keeping blind to the beam in his own...

Spoken like a true expert of being blind of some things. ;)

(Although, I agree with you that the implied judgements made by Chugger&co were irrelevant and unconstructive, not to say stupid, but admittedly it's hard to discuss with you when you behave in a so obtuse way).

[DivisibleByZero]

(Although, I agree with you that the implied judgements made by Chugger&co were irrelevant and unconstructive, not to say stupid, but admittedly it's hard to discuss with you when you behave in a so obtuse way).

He says, as he calls me obtuse.

[Willie the Duck]

1) To me it seems strange that what type of battle mat you play on could affect the mechanics of how a spell works. And it is extremely clear that the normal rule is for movement to be one foot at a time, given that "Playing on a Grid" says "Rather than moving foot by foot...".

The thing is, we're already at the point of 'dark ages monks debating the number of angels dancing on pinheads' level of over-analysis. The designers, in my opinion wisely, took a very 'Rulings not Rules, so you will hopefully shut up about RAW' stance. This is past the rules granularity that they intended. Therefore, in my mind, it's not inconceivable that the 'actual rules' would create genuinely absurd outcomes.


might even have autism or an issue similar to it.

just. don't.

Seriously.

As to your and DBZ's debate, I will not address the meat of the argument, or who I think is right, simply the method of argument and how the case has been made. To the actual ruling, I do not care. I lived through the late 3e era on the WotC board, with people using publication dates of different books as 'proof' of how 'right' they were and decided that no one won in RAW debates and those who lost were those gamers who tried to argue to their friends that gaming was in fact the hobby of mature, intelligent individuals with this bat**** going on in the background.

Anyways


The lead designer and rules sage has answered the question. The rules support exactly the statement that he made. You guys are trying to do mental gymnastics claiming that he was answering a different question, but the fact is that he wasn't. He simply quoted the relevant rule. That rule is also relevant to the stacking question posed here. It's the same answer for the same rule, because it is in essence the same question, just worded differently. Even if it weren't the same question, which it essentially is, the rule is and would still be relevant. That rule states that the same spell doesn't stack with itself. Word the question any way that you want to, it gets the same answer. No stacking.

what you are basically doing right now is very vocally saying 'guy in charge answered this <link> question and this situation is exactly the same. They're the same! They're the same!' You're just insisting that they are the same really loudly instead of providing an actual argument towards that position.


It absolutely is normal for otherwise very smart people to get caught up or be "blind" to certain things. That's exactly what you guys are doing by ignoring the fact that the question has been asked and answered, with that answer pointing to the relevant rule.

Even if you are right, this is not the argument that would solidify your case, so you'd be right despite your best efforts. Make a case that they are the same situation, don't try to browbeat people until they just give up and leave, because you certainly won't convince anyone that way.


I'm not the one twisting the question and the answer because I don't like it. Therefore, I'm not the one being irrational.

it sure seems that way to the outsider, in both cases.

[orange74]

Let's look at this a different way.

Let's suppose I'm wielding a halberd, which extends my reach to 10'.

I am standing adjacent to an opponent -- for the sake of argument, we'll assume we're on a grid here, and he is standing directly north of me. I cast booming blade and hit him with my halberd.

On his turn, the bad guy moves. Let's say he is going to use his entire movement to move directly away from me, that is, north. When he leaves his starting square, this causes the secondary damage of booming blade to go off.

There is now one square separating us. He continues moving northward, directly away from me. Just before he leaves my reach, he triggers an OA. I use warcaster and cast booming blade again, and hit. As he moves (now into a position with two squares separating us) he triggers the secondary damage of booming blade to go off again.

Is this how things go, according to RAW? If not, why not?

[DivisibleByZero]

Let's look at this a different way.

Let's suppose I'm wielding a halberd, which extends my reach to 10'.

I am standing adjacent to an opponent -- for the sake of argument, we'll assume we're on a grid here, and he is standing directly north of me. I cast booming blade and hit him with my halberd.

On his turn, the bad guy moves. Let's say he is going to use his entire movement to move directly away from me, that is, north. When he leaves his starting square, this causes the secondary damage of booming blade to go off.

There is now one square separating us. He continues moving northward, directly away from me. Just before he leaves my reach, he triggers an OA. I use warcaster and cast booming blade again, and hit. As he moves (now into a position with two squares separating us) he triggers the secondary damage of booming blade to go off again.

Is this how things go, according to RAW? If not, why not?

Yes, but only if you have the Spell Sniper Feat to extend BB's range, which is otherwise 5' and can't be used with a polearm's range, and only then if you're houseruling that OAS happen at your reach instead of the 5' mark listed in the description for OAS. So this requires an houserule, and a feat, and a specific circumstance. But you're talking about an houseruled outlier with a reach weapon, an enemy starting adjacent, and that enemy triggering BB from movement before moving away and allowing an OA.
This is a similar situation to the OP, where the enemy travels/moves a distance which remains adjacent *before* moving away.

That's not what we're debating.
We're debating whether that first 5' movement can proc BB twice. The rules say no.

[dejarnjc]

I dunno why you guys bother. I've never seen this guy admit that he's wrong in any of the countless arguments he gets into in these forums. Spare yourselves the time and the inevitable headache and just ignore him.

[Aett_Thorn]

Let's look at this a different way.

Let's suppose I'm wielding a halberd, which extends my reach to 10'.

I am standing adjacent to an opponent -- for the sake of argument, we'll assume we're on a grid here, and he is standing directly north of me. I cast booming blade and hit him with my halberd.

On his turn, the bad guy moves. Let's say he is going to use his entire movement to move directly away from me, that is, north. When he leaves his starting square, this causes the secondary damage of booming blade to go off.

There is now one square separating us. He continues moving northward, directly away from me. Just before he leaves my reach, he triggers an OA. I use warcaster and cast booming blade again, and hit. As he moves (now into a position with two squares separating us) he triggers the secondary damage of booming blade to go off again.

Is this how things go, according to RAW? If not, why not?

Yes, you are absolutely correct. Having a reach weapon apparently makes this easier, as there is a clearer order of operations. The move that triggers the original BB damage and the AoO happen at different barriers.

When a non-reach weapon is involved, apparently it gets a bit trickier, as there is no explicit order of operations involved. However, I still say that based on the language of BB and AoO, that the move that triggers the BB damage happens before the AoO, which means that the AoO BB would lead to a second, non-overlapping application of BB, which would then trigger if the target moved further away. A single 5' movement would never trigger two BB applications, but 10' of movement could.

[Aett_Thorn]

I dunno why you guys bother. I've never seen this guy admit that he's wrong in any of the countless arguments he gets into in these forums. Spare yourselves the time and the inevitable headache and just ignore him.

Well if he'd just admit that he's arguing a point that none of the rest of us are, that might be a start.

[Aett_Thorn]

That's not what we're debating.
We're debating whether that first 5' movement can proc BB twice. The rules say no.

Absolutely nobody here is arguing that the first 5' of movement can proc BB twice. NOBODY. We are arguing that the first 5' of movement expends the first BB, and allows a second application of BB due to the AoO. But the 5' of movement would NOT proc BB a second time. But an additional 5' of movement would proc the second casting of BB that comes from the AoO.

[DivisibleByZero]

Absolutely nobody here is arguing that the first 5' of movement can proc BB twice. NOBODY. We are arguing that the first 5' of movement expends the first BB, and allows a second application of BB due to the AoO. But the 5' of movement would NOT proc BB a second time. But an additional 5' of movement would proc the second casting of BB that comes from the AoO.

No, because OAs interrupt the movement, which means the first 5' HAS NOT BEEN MOVED YET when the second BB is cast. If it hasn't been moved yet, then the first BB has not triggered.
Ipso Facto, that 5' of movement triggers BB twice, according to your line of reasoning.
Either that, or you're allowing BB to be cast, the second time, outside of its 5' range. Because if the first 5' of movement moves him away, then the enemy isn't in range to even cast BB again.

This is precisely why I lead with:
Depends on when your DM rules the first one to proc. Is it when the enemy begins his move, or when he actually leaves the space, or what?

[Aett_Thorn]

No, because OAs interrupt the movement, which means the first 5' HAS NOT BEEN MOVED YET when the second BB is cast. If it hasn't been moved yet, then the first BB has not triggered.
Ipso Facto, that 5' of movement triggers BB twice, according to your line of reasoning.

Can you show me where you are getting that OAs interrupt the movement? I am AFB right now, and all of the sources that I can find give this as the language used:

"In a fight, everyone is constantly watching for a chance to strike an enemy who is fleeing or passing by. Such a strike is called an opportunity attack.
You can make an opportunity attack when a hostile creature that you can see moves out of your reach. To make the opportunity attack, you use your reaction to make one melee attack against the provoking creature. The attack occurs right before the creature leaves your reach.

You can avoid provoking an opportunity attack by taking the Disengage action. You also don’t provoke an opportunity attack when you Teleport or when someone or something moves you without using your Movement, action, or reaction. For example, you don’t provoke an opportunity attack if an explosion hurls you out of a foe’s reach or if gravity causes you to fall past an enemy."


Nothing in there about interrupting the movement.

[DivisibleByZero]

Can you show me where you are getting that OAs interrupt the movement? I am AFB right now, and all of the sources that I can find give this as the language used:

"In a fight, everyone is constantly watching for a chance to strike an enemy who is fleeing or passing by. Such a strike is called an opportunity attack.
You can make an opportunity attack when a hostile creature that you can see moves out of your reach. To make the opportunity attack, you use your reaction to make one melee attack against the provoking creature. The attack occurs right before the creature leaves your reach.

You can avoid provoking an opportunity attack by taking the Disengage action. You also don’t provoke an opportunity attack when you Teleport or when someone or something moves you without using your Movement, action, or reaction. For example, you don’t provoke an opportunity attack if an explosion hurls you out of a foe’s reach or if gravity causes you to fall past an enemy."


Nothing in there about interrupting the movement.

Reactions happen after the trigger, unless timing is specified otherwise.
In this case, the trigger is moving 5' away from you, which puts the enemy outside of your melee range normally. This creates a paradox wherein you got to attack, but cannot because the enemy is no longer in range.
So OAs, be default, interrupt.
Confirmed here:
--uzury @liviotupi
When you hit with an OA you interrupt the movement. The move is wasted or he can resume his move with the same
--Jeremy Crawford @JeremyECrawford
Can resume


Also confirmed in a bunch of other places. OAs interrupt movement, because they create a paradox if they don't.
Feel free to ask JC if you think I'm wrong, but he has already confirmed what I'm telling you, as I'm certain you'll find if you research it on your own.

[Citan]

He says, as he calls me obtuse.
There is a big difference in saying "this guy IS obtuse" and "this guy is BEHAVING in an obtuse way".
First is making a judgement on the person's essence. Second is making a judgement on a specific set of this person's words or acts, without ever denying the person's intrinsical value.

The fact that you don't even understand that simple but essential nuance explains much about how and why you are unable to understand all rules in a clear manner. :)
Whether are not English is your native language, there is a minimum level to have to enjoy complex things such as roleplays. :)

[Contrast]

The attack occurs right before the creature leaves your reach.

Per the above, the opp attack triggers before the target has actually used any movement (unless of course you are using a polearm). Hence why sentinel stops someone before they move rather than after they move and opportunity attacks can even hit as otherwise the target would be out of range.

[Dudewithknives]

Can you show me where you are getting that OAs interrupt the movement? I am AFB right now, and all of the sources that I can find give this as the language used:

"In a fight, everyone is constantly watching for a chance to strike an enemy who is fleeing or passing by. Such a strike is called an opportunity attack.
You can make an opportunity attack when a hostile creature that you can see moves out of your reach. To make the opportunity attack, you use your reaction to make one melee attack against the provoking creature. The attack occurs right before the creature leaves your reach.

You can avoid provoking an opportunity attack by taking the Disengage action. You also don’t provoke an opportunity attack when you Teleport or when someone or something moves you without using your Movement, action, or reaction. For example, you don’t provoke an opportunity attack if an explosion hurls you out of a foe’s reach or if gravity causes you to fall past an enemy."


Nothing in there about interrupting the movement.

It does say it interrupts the movement.

It does NOT say it happens before they move.

If you are standing next to an enemy and they decide to leave your threatened range, you interrupt them immediately before they leave your threatened area, not before they move at all.

If they were going to move 30 feet you would interrupt them at 5, not before they ever took a step.

They move at all, booming blade activates, they pass your threatened area, AoO happens and you booming blade again, their movement continues and 2nd booming blade activate.

[RickAllison]

To me, it seems rather clear because of the interaction of opportunity attacks with other effects.

1) Sentinel reduces speed to 0' after the OA and you have the option to not trigger a Warcaster Booming Blade. This means that if any movement is required to trigger an OA, it must occur beforehand.

2) Booming Blade triggers if you move. With 1, this means that if any movement is required to trigger an OA, Booming Blade must go off beforehand.

3) Does an OA require movement to trigger? Or is it just the intent to move? If the former, you potentially can get the damage of both. If the latter, then the rules are weird.

[DivisibleByZero]

To me, it seems rather clear because of the interaction of opportunity attacks with other effects.

1) Sentinel reduces speed to 0' after the OA and you have the option to not trigger a Warcaster Booming Blade. This means that if any movement is required to trigger an OA, it must occur beforehand.

2) Booming Blade triggers if you move. With 1, this means that if any movement is required to trigger an OA, Booming Blade must go off beforehand.

3) Does an OA require movement to trigger? Or is it just the intent to move? If the former, you potentially can get the damage of both. If the latter, then the rules are weird.

An OA requires movement to trigger, but interrupts that movement and happens before the movement did.
That's why the Sentinel feat can OA to stop an enemy's movement before it happens.
So for all of this, the first BB hasn't gone off yet, because he hasn't moved yet, because the OA triggers upon the movement but interrupts and happens first, and is replaced with a second BB, which then finishes the OA and allows the creature to actually move. But now he has two instances of BB on him, and only one goes off due to the prohibition of spell stacking.

Cast BB on enemy.
Enemy moves.
That movement doesn't happen because it procs an OA which happens first. So the enemy hasn't *actually* moved yet, which means the first BB hasn't actually triggered yet.
The OA is replaced by BB via WC.
Now the enemy has two instances of BB on him. The OA/WW-BB has finished, and the enemy completes the move.
One instance of BB goes off, and not a second one, because they're stacked.

[ThePolarBear]

Let's look at this a different way.

Let's suppose I'm wielding a halberd, which extends my reach to 10'.

I am standing adjacent to an opponent -- for the sake of argument, we'll assume we're on a grid here, and he is standing directly north of me. I cast booming blade and hit him with my halberd.

On his turn, the bad guy moves. Let's say he is going to use his entire movement to move directly away from me, that is, north. When he leaves his starting square, this causes the secondary damage of booming blade to go off.

There is now one square separating us. He continues moving northward, directly away from me. Just before he leaves my reach, he triggers an OA. I use warcaster and cast booming blade again, and hit. As he moves (now into a position with two squares separating us) he triggers the secondary damage of booming blade to go off again.

Is this how things go, according to RAW? If not, why not?

No, this does not work, RAW, since Warcaster doesn't give you another way to use a special AoO, but it simply uses the same trigger that the AoO uses (a creature leaves) and allows a different reaction to be taken (can cast a spell bla bla).

"Rather than making an AoO" - Not an AoO. Since it's the attack that interrupts the movement, if you do not make the attack you do not gain any interruption.

Since the different reaction - let's call it WCreaction - has no special timings on when it's conducted the default applies: after the trigger.

After the trigger - the creature has left your reach - you take the WCreaction and can cast a spell. Since you do not specify any ability to cast BB at 15' range, you can't cast BB. Even if you could, you couldn't strike without some other ability further extending your reach on top of the weapon propriety.

Everyone is hung up on "you take an AoO". The WCreaction is not an AoO and doesn't follow the rules for AoOs. It simply uses the same trigger.

[Spiritchaser]

An OA requires movement to trigger, but interrupts that movement and happens before the movement did.
That's why the Sentinel feat can OA to stop an enemy's movement before it happens.
So for all of this, the first BB hasn't gone off yet, because he hasn't moved yet, because the OA triggers upon the movement but interrupts and happens first, and is replaced with a second BB, which then finishes the OA and allows the creature to actually move. But now he has two instances of BB on him, and only one goes off due to the prohibition of spell stacking.

Cast BB on enemy.
Enemy moves.
That movement doesn't happen because it procs an OA which happens first. So the enemy hasn't *actually* moved yet, which means the first BB hasn't actually triggered yet.
The OA is replaced by BB via WC.
Now the enemy has two instances of BB on him. The OA/WW-BB has finished, and the enemy completes the move.
One instance of BB goes off, and not a second one, because they're stacked.

That’s certainly one interpretation. It’s not how I would assess it in the general case

Some level of motion is needed to trigger booming blade
Some level of motion is needed to trigger an OA
In both cases this is more than it takes to dodge... maybe it’s a foot, maybe it’s a determined weight shift... in the case of booming blade it’s magic so anything goes. It’s more than a little vague. In any case, barring other information, which we don’t have, there’s no particular reason to presume that war caster procs before booming blade.

To presume such is to read something into the rules that isnt there.

Now: there may be a good reason to do so. I haven’t really thought enough about how exploitable the double proc is.

You might be able to make a solid argument that this shouldn’t be allowed to happen.

You have not convinced me that there is anything in the raw that prevents it from happening. Quite the opposite, you’ve helped clarify how the competing view is most “correct”.

That doesn’t make it “right”

[DivisibleByZero]

No, this does not work, RAW, since Warcaster doesn't give you another way to use a special AoO, but it simply uses the same trigger that the AoO uses (a creature leaves) and allows a different reaction to be taken (can cast a spell bla bla).

"Rather than making an AoO" - Not an AoO. Since it's the attack that interrupts the movement, if you do not make the attack you do not gain any interruption.

Since the different reaction - let's call it WCreaction - has no special timings on when it's conducted. So, the default applies: after the trigger.

After the trigger - the creature has left your reach - you take the WCreaction and can cast a spell. Since you do not specify any ability to cast BB at 15' range, you can't cast BB. Even if you could, you couldn't strike without some other ability further extending your reach on top of the weapon propriety.

Everyone is hung up on "you take an AoO". The WCreaction is not an AoO and doesn't follow the rules for AoOs. It simply uses the same trigger.

By this reasoning, GFB and BB are ineligible for WC reactions, as the enemy is no longer within 5' to cast them at all.
I think it's safe to assume that DMs will almost always follow the OA timing and interrupt, or else ban these (and any other melee reach) spells from being used with WC to begin with.


That’s certainly one interpretation. It’s not how I would assess it in the general case

Some level of motion is needed to trigger booming blade
Some level of motion is needed to trigger an OA
In both cases this is more than it takes to dodge... maybe it’s a foot, maybe it’s a determined weight shift... in the case of booming blade it’s magic so anything goes. It’s more than a little vague. In any case, barring other information, which we don’t have, there’s no particular reason to presume that war caster procs before booming blade.

To presume such is to read something into the rules that isnt there.

Now: there may be a good reason to do so. I haven’t really thought enough about how exploitable the double proc is.

You might be able to make a solid argument that this shouldn’t be allowed to happen.

You have not convinced me that there is anything in the raw that prevents it from happening. Quite the opposite, you’ve helped clarify how the competing view is most “correct”.

That doesn’t make it “right”

And you're perfectly within your rights to rule it that way, or any other way that you want to for that matter.
But within the confines of a discussion of the RAW, and the order of operations, this requires spell stacking, which is prohibited.

[Aett_Thorn]

I honestly think that the way people view the grid is the problem here. The grid should just be used to facilitate interactions, but it doesn't negate logic.

If we're playing Theater of the Mind here, then BB would have to occur before the AoO. Since the movement of 1' would necessarily happen before the movement of 5' out of reach. In this case, the "interrupt" of the movement would happen between 4' and 5', not at 0'. So BB could be reapplied.

If you're using a grid, movement becomes 5' minimums, because that is the size of the square. However, I don't think that it negates the logical process that you need to move 1' before you can move 5'. If characters are standing in the middle of each square normally, it needs to somehow get to the edge of the square to provoke the WCreaction in the first place, even if the WCreaction "interrupts" the movement.

Since the vast majority of spells or effects really don't care about the order of operations, for the most part it's a moot point, and really only BB and Sentinel have any impact on how this order of operations goes. And since Sentinel is a specific > general change, and involves specifically an AoO, then it doesn't matter here. As such, BB is just an odd duck within the language of 5e, when used on a grid. It provokes an order of operations argument that doesn't exist anywhere else in the game that I am aware of.

[DivisibleByZero]

I honestly think that the way people view the grid is the problem here. The grid should just be used to facilitate interactions, but it doesn't negate logic.

Grid has nothing to do with it.

Space (pg 191)
A creature's space is the area in feet that it effectively controls in combat, not an expression of its physical dimensions. A typical Medium creature isn't 5 feet wide, for example, but it does control a space that wide. If a Medium hobgoblin stands in a 5-foot-wide doorway, other creatures can’t get through unless the hobgoblin lets them.
A creature’s space also reflects the area it needs to fight effectively. For that reason, there’s a limit to the number of creatures that can surround another creature in combat. Assuming Medium combatants, eight creatures can fit in a 5-foot radius around another one.

You can dance around and move around within that 5'x5' space as much as you like. That's what happens in hand to hand combat. You aren't a statue, patiently awaiting your turn to swing your sword. You're constantly shuffling your feet and repositioning yourself within that 5'x5' space.
But as far as the game is concerned, you haven't actually moved until you leave that 5'x5' space. I'm not talking about a 5' square on a grid, although that can certainly be used as an example. I'm talking about the 5'x5' space that you control in combat, whether that be on a grid or in TotM.
Once you do leave that 5'x5' space, if an enemy is within 5' of you, he gets an OA which interrupts your movement (and therefore happens before your movement does). This is when the second BB would be applied, before you actually moved and before the first one has proc'd.
Hence why this is a stacking issue.

[Spiritchaser]

And you're perfectly within your rights to rule it that way, or any other way that you want to for that matter.
But within the confines of a discussion of the RAW, and the order of operations, this requires spell stacking, which is prohibited.

I don’t think you understand me.

Your arguments have helped convince me, rather early in the thread, that spell stacking is never required to occur by RAW, that the first booming blade procs first, before the second is applied.

I’m suggesting that you may still be arguing for the right outcome. it may be right to house rule against RAW in this case to prevent an awkward and exploitable situation that RAW would otherwise create.

[Aett_Thorn]

DBZ:

Found another Sage Advice tweet here: https://www.sageadvice.eu/2015/11/10/war-caster-hitting-with-booming-blade/

"War Caster hitting with Booming Blade when an enemy leaves its reach: can the enemy stop moving to avoid the extra damage?"

Response from JC: "A target hit by an opportunity attack mid-move is in control of its movement, unless somehow compelled."


Notice that JC says "mid-move". Not pre-move. Mid-move. He has already started to move. He can stop moving. But he has already started.

[DivisibleByZero]

DBZ:

Found another Sage Advice tweet here: https://www.sageadvice.eu/2015/11/10/war-caster-hitting-with-booming-blade/

"War Caster hitting with Booming Blade when an enemy leaves its reach: can the enemy stop moving to avoid the extra damage?"

Response from JC: "A target hit by an opportunity attack mid-move is in control of its movement, unless somehow compelled."

Notice that JC says "mid-move". Not pre-move. Mid-move. He has already started to move. He can stop moving. But he has already started.

What you apparently fail to see here is that he can absolutely choose not to make that move and that this means that obviously the move hasn't happened yet.

Can the enemy stop moving to avoid the extra damage?
Paraphrased answer: YES.
So if he has already moved, how can he stop moving to avoid the extra damage? How can he avoid something which has already happened?
All you're doing is confirming what I've been telling you.

[Aett_Thorn]

What you apparently fail to see here is that he can absolutely choose not to make that move and that this means that obviously the move hasn't happened yet.

Can the enemy stop moving to avoid the extra damage?
Paraphrased answer: YES.
So if he has already moved, how can he stop moving to avoid the extra damage? How can he avoid something which has already happened?
All you're doing is confirming what I've been telling you.

If the move hasn't happened yet, then you don't get to make the AoO. It becomes a paradox at that point. Because then you wouldn't have been able to do the AoO that is now causing him to stop. So he doesn't move, and you don't get the AoO, so he is free to move again without taking damage, which prompts an AoO.

He gets hit with the AoO as he crosses the boundary of your reach, so he moves 5', he is then in the next square, surrounded by booming energy. He can then stop moving any further, and not take the damage. He doesn't take the damage because he hasn't moved from the square that he is in at the end of your AoO.

[DivisibleByZero]

He gets hit with the AoO as he crosses the boundary of your reach, so he moves 5', he is then in the next square, surrounded by booming energy. He can then stop moving any further, and not take the damage. He doesn't take the damage because he hasn't moved from the square that he is in at the end of your AoO.


First of all, that's not how timing on OAs works. They interrupt, as I keep telling you. That means that they happen before the movement. This is why Sentinel can stop you in your tracks with an OA and reduce your movement to zero.
How can your movement be zero if you've already moved?
Easy, because OAs happen before movement. They interrupt.
It didn't happen as they crossed any threshold. That's in your head. What happened is that they moved 0 and stayed exactly where they were before.

In response to what you wrote:
He isn't in the next square. If he were, he'd be out of your reach and you wouldn't be able to attack him in the first place.
So either A) he is in the original square, and hasn't moved, and therefore hasn't proc'd BB, and therefore this would be stacking, or B) he has moved, and he has proc'd BB, and he is in the next square as you claim, and therefore is no longer within range of the spell so you can't even cast a second BB on him.
You can't have both.

[Asmotherion]

The way you describe it, since it was already trigered before the second casting of the spell, yeah, seems correct.

Just to be sure, I'd use a Glaive or some other Reach Weapon, and take the Spell Sniper Feat on the next ASI; Booming Blade's range is listed as 5 feet, and Spell Sniper requires the spell to need an attack roll (does not specify a spell attack roll). This way, your range is 10 feet, and you can use it on escaping foes twice.

Finally, get Pole-arm Master, and do so even when enemies come at you, instead of only when they leave your reach.

That's my default feat chain when I play a Warlock/Sorcerer as a Gish. A Hexblade 5/Red Dragon Ancestry 8 I played in a oneshot used this trick by quickening Booming Blade, then casting Green-Flame Blade, and using Booming Blade on Aproaching opponents.

It's practically the old PAM+Sentinel, but instead of lockdown, you deal extra damage.

[ThePolarBear]

By this reasoning, GFB and BB are ineligible for WC reactions, as the enemy is no longer within 5' to cast them at all.
I think it's safe to assume that DMs will almost always follow the OA timing and interrupt, or else ban these (and any other melee reach) spells from being used with WC to begin with.

Exacly, those spells are ineligible for reactions unless also coupled with Spell Sniper and the ability to hit at 10ft.

The fact that most DM assume something doesn't make anyone "righter".
Even the fact that for designers this is correct would not make it RAW. It makes it RAI.

The intention would be that you can in fact use it. But you can also cast, i dunno, firebolt without getting disadvantage if you rule it so? The answer at that point would be no, you have disadvantage since you have a creature next to you. Or yes, since the creature is not paying attention to you, as DM adjudication.

Or you can simply say that RAW is "no, can't use it", everyone else and i think the designers too play it differently and you do you with your group.

But the question is "is it ok by the books". And the answer is no, it's not.

Edit: I would be thrilled for a complete official answer on this - even more for an errata. It can go both ways easily (but my BB! but my scorching ray!). I simply answered with what i read to be the answer with reasoning that doesn't hinge on "it must work so it has to be so" or "it mustn't work so it has to be so".

[Aett_Thorn]

DBZ: I'd say that the Developers are just as confused on this as we are:

https://www.sageadvice.eu/2016/03/04/will-booming-blade-trigger-before-the-sentinel-feature-takes-effect/

In those two tweets, we see that Mike Mearls says that BB's damage doesn't occur until the creature spends 5' of movement, but that the damage from BB would come BEFORE a Sentinel-affected OA, which by your understanding would happen before the move.

[DivisibleByZero]

DBZ: I'd say that the Developers are just as confused on this as we are:

https://www.sageadvice.eu/2016/03/04/will-booming-blade-trigger-before-the-sentinel-feature-takes-effect/

In those two tweets, we see that Mike Mearls says that BB's damage doesn't occur until the creature spends 5' of movement, but that the damage from BB would come BEFORE a Sentinel-affected OA, which by your understanding would happen before the move.

That isn't what he said at all.
What he said completely coincides with what I've been saying.
"i believe the creature then takes damage, unless it opts to stop moving immediately and stay in your reach "

He obviously missed the fact that the question was in regards to using the Sentinel feat, or his answer wouldn't have included "opt[ing] to stop moving immediately," because with Sentinel it isn't an option.

Not that anyone is going to listen to Mearls on this one anyway, but Mearls did indeed confirm what I've been saying.
If he stops moving and stays within your reach, no damage from BB.
Meaning the OA happens before the move completes, and that the damage from BB doesn't occur until the move completes 5' or more.

You just proved me right, if you want to listen to Mearls.

[Aett_Thorn]

That isn't what he said at all.
What he said completely coincides with what I've been saying.
"i believe the creature then takes damage, unless it opts to stop moving immediately and stay in your reach "

He obviously missed the fact that the question was in regards to using the Sentinel feat, or his answer wouldn't have included "opt[ing] to stop moving immediately," because with Sentinel it isn't an option.

Not that anyone is going to listen to Mearls on this one anyway, but Mearls did indeed confirm what I've been saying.
If he stops moving and stays within your reach, no damage from BB.
Meaning the OA happens before the move completes, and that the damage from BB doesn't occur until the move completes 5' or more.

You just proved me right, if you want to listen to Mearls.

Man, you and I just read these things very differently.

I read it as: "The creature begins to move, it takes BB damage, then provokes an AoO where Sentinel would affect it. However, it can choose to stop before it takes BB damage, at which point it has stopped moving and will not provoke an AoO."

Edit -> This is also probably why 140-character tweets aren't great places for rules discussions.

[DivisibleByZero]

Man, you and I just read these things very differently.

I read it as: "The creature begins to move, it takes BB damage, then provokes an AoO where Sentinel would affect it. However, it can choose to stop before it takes BB damage, at which point it has stopped moving and will not provoke an AoO."

Edit -> This is also probably why 140-character tweets aren't great places for rules discussions.

You're looking for an answer to a question that wasn't asked.
Provoking an OA is irrelevant to the question.
He was asking about the BB damage, whether it triggers.
The answer was that, if he stops moving, it does not trigger.
The OA does not factor into the answer at all. Not even a little bit.

To paraphrase:
Will BB trigger in this case?
Answer: Yes, unless he chooses to stop moving.

OAs have no relevance to this. As I said, he missed the fact that the question was in regards to Sentinel. This is obvious, as Sentinel stops movement involuntarily, and he answered as if it were a voluntary choice. He answered as if you could choose to keep moving, which is not the case with Sentinel. So Sentinel doesn't factor into the answer at all. Since Sentinel doesn't factor into the answer at all, neither does the OA.
The question was about primarily about BB damage, and that's what was answered. Mearls completely ignored the entire part about the OA in the answer. The OA does not factor into the answer at all. The answer given was completely in regards to the BB damage.

[Aett_Thorn]

You're looking for an answer to a question that wasn't asked.
Provoking an OA is irrelevant to the question.
He was asking about the BB damage, whether it triggers.
The answer was that, if he stops moving, it does not trigger.
The OA does not factor into the answer at all. Not even a little bit.

The question was about whether or not the OA from Sentinel would stop the BB damage, since it would drop the creature's speed to zero! How is that not a factor?

Q: Will booming blade trigger before the Sentinel feature takes effect? Opportunity attacks happen just before they leave reach.

A: i believe the creature then takes damage, unless it opts to stop moving immediately and stay in your reach

Provoking an OA is entirely relevant to the question, since it is specifically part of the question!

1) Creature is going to leave your reach, this will trigger both BB and an OA, since an OA happens just before they leave reach.

2) An OA from a player with Sentinel will drop the target's speed to zero.

3) So which happens first, the BB damage, or the OA from Sentinel?

4) Answer: the BB damage first, unless the creature decides not to move after all to avoid it.


Now, you can say not to trust Mearls, or that he is ignoring a part of the question, but I really don't see how you can say that the OA is irrelevant to the question.

[DivisibleByZero]

That was the question asked.
That was NOT the question answered.
Read my edit, above.

Again:
To paraphrase:
Will BB trigger in this case?
Answer: Yes, unless he chooses to stop moving.

The answer he gave is impossible and nonsensical, unless you take into account that he completely missed the relevance of Sentinel here, and simply answered as I explained above.
"unless he opts to stop moving" proves this.
Sentinel forces you to stop. You don't get a choice. So the fact that he answered as if you get a choice means that Sentinel is not a factor in his response. He missed that part.

If you want to dispute this, then you need to explain to me how his answer makes a single shred of sense.
It doesn't. The only way his answer makes sense is if he missed the part about Sentinel.
If you take that into account, his answer goes from being nonsensical and contradictory to suddenly making perfect sense.

[Garret Dorigan]

Ok, while this may be a certain level of pedantry, I think there needs to be some jargon clarification here. There are three types of rules approximations that are applicable here; RAW or Rules as Written, RAT or Rules as Interpreted, and RAI or Rules as Intended.

In reverse order, RAI would be JC's determination on the subject... which I want to point out that previous tweets allude to a similar situation that we can glean a lot from, but not an official ruling on it as this specific instance has not been levied before him.

RAT would be what is given in the OP, as that is the decision that was made at the table by the DM in the moment.

RAW is a slippery slope, as getting the RAW of a situation requires a level of reading as if you were a Magic: The Gathering Pro Tour judge, wherein you look at supporting language down to the word to figure out a solution that the reading supports, both in the effected text and other text that uses similar or the same language.

So, for the RAW example:


An initiating creature uses it's action to cast Booming Blade against another hostile creature within 5 feet of it
The attack roll of Booming Blade resolves to a hit, and the initial effect of the Booming Blade spell are also resolved
The secondary effect of Booming Blade applies it's state-dependent trigger to the affected hostile creature
The affected hostile creature of the secondary effect of Booming Blade declares that it is using it's movement to move
The affected hostile creature is willingly moving and immediately takes the damage afforded by the state listed in the secondary effect of the Booming Blade spell
Damage for the secondary effect of Booming Blade is resolved
As the hostile creature performs it's movement and has used enough to be crossing out of the reach of the initiating creature, a state-dependent effect is applied to the hostile creature of provoking an opportunity attack from the initiating creature
The initiating creature is afforded the decision to use his reaction for the state-dependent effect trigger of the hostile creature provoking an opportunity attack
The initiating creature chooses to use his reaction to perform the opportunity attack
Upon this choice, the initiating creature is afforded a choice based state-dependent trigger to use the third effect of the Warcaster feat to cast a spell, rather than making an opportunity attack
The initiating creature chooses to use the third effect of the Warcaster feat to cast a spell, rather than making an opportunity attack
The initiating creature chooses Booming Blade from the spells that it knows, as it fits the requirements of the third effect of the Warcaster feat
The attack roll of Booming Blade resolves to a hit, and the initial effect of the Booming Blade spell are also resolved
The secondary effect of Booming Blade applies it's state-dependent trigger to the affected hostile creature
The affected hostile creature is willingly moving and immediately takes the damage afforded by the state listed in the secondary effect of the Booming Blade spell
Damage for the secondary effect of Booming Blade is resolved


Note that nowhere in the description of Opportunity Attack (unless there has been official errata that I'm not seeing or a reprinting of) does it list that an Opportunity Attack disrupts movement. It occurs right before the creature leaves your reach, as written, whereas the secondary effect of Booming Blade happens immediately upon willing movement (that is, by use of a move) of the affected hostile creature, as written. As written, any time that a creature uses any of it's movement for the round, up to it's speed, it immediately resolves Booming Blade's secondary effect, if it is affected by it. These two state-dependent triggers are not mutually exclusive.

Also note that the above list isn't actually RAW, as I haven't exhaustively searched for like language in other spells, effects, and actions to support or tear down the steps, and listed these supporting things as footnotes.

That is why RAW is a slippery slope, and that following RAI is usually much better/easier... which is the entire reason Sage Advice exists.

[DivisibleByZero]

Furthermore, you're completely ignoring the second portion of that interaction, and that's the important one.
He states, in no uncertain terms, that you need to move 5' before BB is triggered.
You cannot dispute this. He states it clear as glass.
That statement alone proves my side of the RAW, if you're willing to accept Mearls' word on things.

[ThePolarBear]

9. The initiating creature chooses to use his reaction to perform the opportunity attack

Actually, the initiating creature does not chose to use the reaction to perform the opportunity attack. Normally, the trigger only applies to AoO. What War Caster does is give the ability to use the reaction when you could use the reaction to make an AoO to cast a spell. You are not using the reaction to make the AoO otherwise you would be left without reactions.

When the trigger happens, he has 2 choices: AoO or WCreaction - mutually exclusive.

It is not worded "When you use your reaction to make an AoO, you can cast a spell instead of making an attack".
It is worded "When a creature provokes an AoO from you, you can spend your reaction to cast a spell instead of making an attack of opportunity."
The Attack of Opportunity is a special attack that is made when you spend a reaction and happens right before the creature leaves.
But you are not making it.

This makes the reaction specifically not an AoO and does not grant any special timing. The reaction is therefore taken when the creature already has completed the movement.


That is why RAW is a slippery slope, and that following RAI is usually much better/easier... which is the entire reason Sage Advice exists.

I agree. I'm being very pedantic. And i would really love an official, clear word on this.

[RickAllison]

I just noticed something else that really deals the deal.

Booming Blade: "Duration: 1 round... If the target willingly moves before then, it immediately takes 1d8 thunder damage, and the spell ends."

So although Booming Blade spells have a duration, they end when the damage triggers. So while three Booming Blades applied before movement don't stack, two Booming Blades with overlapping durations that trigger at different times (theoretically) would because one can resolve while the other has yet to trigger.

From Jeremy Crawford: "A target hit by an opportunity attack mid-move is in control of its movement, unless somehow compelled."
Supporting text from PHB: "You can make an opportunity attack when a hostile creature that you can see moves out of your reach."

An opportunity attack does not exist without prior movement. This has weird ramifications for Sentinel, but it means that the worst case for Booming Blade triggering is that it triggers simultaneously. The two both trigger off the movement in question, and it is just the order that they resolve that matters. Except the order actually doesn't.

If Booming Blade resolves first, we know what happens. The divisive subject is about the OA resolving first. In that case, we have a new application of Booming Blade, but this one differs because it can't trigger yet, as there is another ability that has to trigger. The original Booming Blade resolves and deals damage and ends. This is important because now they don't have overlapping durations anymore.

For reference: "The effects of the same spell cast multiple times don’t combine, however. Instead, the most potent effect—such as the highest bonus—from those castings applies while their durations overlap."

The key difference, DBZ, between the OP situation and the situation proposed to JC is when the duration overlapped. In this situation, you have the first spell that has triggered its damages and ends at the resolution, while the second spell has not triggered.

Of course, this relies on moving out of reach being the trigger for opportunity attacks, that the OA occurs mid-move according to Crawford. This is the RAW way, and the RAI way. You can argue against it and you can certainly make houserules, but every authority on the rules has shown that the OA requires movement. Other aspects can be debated, but as soon as it is declared that the target doesn't move before incurring the OA according to the rules, the speaker is wrong. You can claim it is more balanced or that it makes more sense to not move before the OA, but saying it is by the book is a fallacy.

[Chugger]

I will not seek answers through micro-parsing and word-mincing of what may only be bits of mental methane coming from game developers' Tweets (which quite possibly are not all well thought out).

The real question is one of game balance and do you want BB to potentially go off twice in a round? That's it.

The argument for "no" does not come from combing through JC and Mearl's Tweets and struggling to deduce what they must have meant - that's silly! It seems to me that they don't even know what they meant, and when they Tweet an answer to a related but not spot-on question, they're not answering the question at hand: can you BB twice in a round?

This is more related to "can a rogue Sneak Attack twice in a round?" Some say yes. With haste he can use his hasted shot to get in a Sneak Attack, if I understand the technique correctly, and then Ready his main shot - and word the Ready Action so openly that he almost always gets that shot - and gets another Sneak Attack (because the Readied shot is not on his turn - you only get one Sneak Attack per turn, it's not limited to one per round).

If a DM doesn't like that he can rule at his table that a rogue can only get one Sneak Attack per round. Same with BB. A DM can rule that one target can only receive a BB once per round, end of story. Because this DM wants to limit things and sees such extra damage as "going too far" or "being out of balance" or w/e.

The argument for allowing BB to go twice on one target is that the caster took Warcaster feat instead of something else - and Warcaster "seems to allow it under certain and rare circumstances". And that would be when the target moves the first BB has gone off and thus allows a recasting of BB in an AoO. Yes, you have the problem of "but he moved, so how does the second casting of BB work - the target is out of range" - but you have that problem anyway with an AoO - does the target "start to move" but still stay in range - what does "start to move" even mean - see? If the target moves so much as a nanometer it's technically "out of range" and so no AoO is possible - so there must be some build in fudge factor, i.e. your range is about 5' not exactly 5' - and a lunge of a few feet might be built into all attacks? And that gets messy, too.

So you have to just back off and decide what you want. How do you want things to roll at your table? Do you feel okay with letting someone who spent an ASI on warcaster occasionally get off two bb's per round - seriously how often will this happen - is this really a game-breaker? Are you okay with this idea that they gave up some other advantage on the ASI in picking this particular feat, why not allow it? Or do you feel they got enough power picking this feat and more power (a second bb) is too much? Then just say no - say one bb per target per round is the rule at my table. And be done with it.

There is no Holy Grail here, DBZ. You can argue all you want, but you must step outside the nitty gritty and just pick what you want at your table. Even if JC were to Tweet later today "I've been reading a thread over at GITP and I want to say that DBZ has our logic perfectly and I totally 100% back everything he said" - even if he were to say that - it's meaningless. This is DnD. The rules are only guidelines. It's always been that way. It always will. Count to ten. Take a deep breath through your nose and slowly release it through your mouth while concentrating only on your breathing. Do this several times. I'm not at all being snarky. I'm in all sincerity trying to help you. Good luck.

[DivisibleByZero]

OK, I'll start by repeating what I said as the very first sentence in this thread after the OP.
It depends on when your DM rules that the first BB goes off.

But since you guys want to call me out specifically, by name, I'm going to break this down for you one more time.
Fact 1: BB does not trigger unless you move 5 feet. This is evidenced both by the Space rules on phb191 about the space needed to fight effectively, and by Mearls flat out saying it. Until you move 5', as far as the game is concerned you haven't moved yet.
Fact 2: OAs interrupt movement, and happen first, before the enemy leaves his space. This is evidenced by Sentinel stopping movement, by the paradox created if it doesn't, and by JC confirming it.
Fact 1 and Fact 2 combine to create -
Fact 3: Since BB does not trigger until the enemy has moved 5', and the OA triggers before the enemy has moved 5', this means that the OA happens before BB has triggered. That OA is replaced with another BB.
Fact 4: This means that the second BB is placed on an enemy while the first one still exists.
Fact 5: This then means that when the enemy finally finishes actually moving that 5' and leaves that space, he has two instances of BB, and only one BB triggers, because both cannot trigger off of the same 5' of movement, because spells do not stack with themselves.

Got it yet?

Feel free to rule it however you want to at your table. But if we're discussing the rules, then those are it.

[greenstone]

Only after they have moved at fully out of their threatened area does the attack of opportunity happen.
That's not correct. Attacks of Opportunity occur before the target has moved fully out of the space, because otherwise you wouldn't be able to reach them with your weapon.

From the PHB: "The attack occurs right before the creature leaves your reach."

Additionally, the Sentinel feat's first bullet leaves the target inside your reach (or outside your reach if you are combining Sentinel and Polearm Master).

[MeeposFire]

Booming blade was a decent swordmage at will attack power in 4e and honestly they should have put a little more thought and work adapting it to 5e. The language used in the spell, when you consider how the designers are describing how it should work, still seems to work like it thinks there is still a grid is around but as we all know that is not the default. Now the spell is written so it does not actually require a grid but it is not very descriptive and certain aspects of it fall apart from how it is supposed to work without a grid. This is why the designers had to clarify things like the movement clause did not apply to things like standing up despite it using up your movement and that it requires you to move to stand up. They want it to be like it was in 4e which as it triggers whenever you moved a square or more from your starting position but for some reason they neglected to make the 5e version more explicit in how it works. Really they should have said something akin to "this damage triggers when ever you move voluntarily 5 feet or more from the location you were in when hit".

[gloryblaze]

The real question is one of game balance and do you want BB to potentially go off twice in a round? That's it.


That is, unfortunately, definitively not the question. All members of the thread (including DBZ, as far as i can tell) agree that BB can go off twice in a round. Here's how (P = player, E = enemy, X = empty space):

PXX -> PXX -> PXX
EXX -> XEX -> XXE

In grid state 1, P has cast BB on E and it has not triggered. On E's turn, E moves so that grid state 2 applies. E has moved 5 feet, so BB goes off (per everybody's definition, including DBZ). E is still within 5 feet of P so no OA or WCReaction can take place. It is still E's turn, and they continue to move such that the third grid state applies. At this point, they provoke an OA. P can choose to forgo this OA and instead take the WCReaction to cast BB, which occurs BEFORE the 5-foot movement is completed. When E completes the 5-foot movement, the second BB goes off.

The "real question" to use your term is what happens in the following series of grid states:

PEX -> PXE

Does the first BB resolve before or after the second is applied? If yes, then two BBs proc during the turn, as with the previous example. If the WCReaction occurs and applies the second BB before the first triggers, stacking occurs and thus one of the two BBs is lost.

EDIT: humorously enough, if we agree with DBZ and say that Scenario 1 triggers 2 BBs and Scenario 2 does not, it means that E's optimal movement in S1 would be as follows, doing a little diagonal jig at the start to avoid the double BB trigger:

PXX -> PXX -> PXX
EXX -> XXX -> XXE
XXX -> XEX -> XXX

Call it an argument for diagonal movement costing 1.5 squares like the old days :tongue:

[ThePolarBear]

Fact 2: OAs interrupt movement, and happen first, before the enemy leaves his space. This is evidenced by Sentinel stopping movement, by the paradox created if it doesn't, and by JC confirming it.



That's not correct. Attacks of Opportunity occur before the target has moved fully out of the space, because otherwise you wouldn't be able to reach them with your weapon.

From the PHB: "The attack occurs right before the creature leaves your reach."

Exactly.

However you are not making the attack of opportunity. You are not spending the reaction to make an attack of opportunity but to cast a spell. It's a different reaction that has not "the attack occurs right before the creature leaves your reach" since you never take the attack.

You make an attack as part of casting BB, but the attack is not an AoO.

[Lombra]

Exactly.

However you are not making the attack of opportunity. You are not spending the reaction to make an attack of opportunity but to cast a spell. It's a different reaction that has not "the attack occurs right before the creature leaves your reach" since you never take the attack.

You make an attack as part of casting BB, but the attack is not an AoO.

The trigger is the same, so it happens at the same time of an OA. It is not an OA, but it happens under the same conditions. It's written in the feat.

[ThePolarBear]

The trigger is the same, so it happens at the same time of an OA. It is not an OA, but it happens under the same conditions. It's written in the feat.

It happens in response to the same trigger, yes. But it doesn't specifically happen at the same time, since it is NOT written in the feat. In the feat is written that you can take that reaction instead of making an attack of opportunity and for rules of reaction if a reaction has a special timing it has to be described as such in the reaction, otherwise it happens at the default timing: when the trigger has been completed.

The trigger for an AoO is that a creature leaves the reach. The AoO has a built in exception that makes "the attack occurs right before the creature leaves your reach". WC does not change the timing for the spell.

[Lombra]

It happens in response to the same trigger, yes. But it doesn't specifically happen at the same time, since it is NOT written in the feat. In the feat is written that you can take that reaction instead of making an attack of opportunity and for rules of reaction if a reaction has a special timing it has to be described as such in the reaction, otherwise it happens at the default timing: when the trigger has been completed.

The trigger for an AoO is that a creature leaves the reach. The AoO has a built in exception that makes "the attack occurs right before the creature leaves your reach". WC does not change the timing for the spell.

So you would say that melee spells can't benefit from WC unless the caster has spell sniper, and that ranged spell attacks actually work as normal, without disadvantage, when performed as a reaction through war caster?

[DivisibleByZero]

So you would say that melee spells can't benefit from WC unless the caster has spell sniper, and that ranged spell attacks actually work as normal, without disadvantage, when performed as a reaction through war caster?

Has saying that's technically the RAW, yes, and technically he's correct. But no one is probably going to play it that way, like, ever.

[ThePolarBear]

So you would say that melee spells can't benefit from WC unless the caster has spell sniper, and that ranged spell attacks actually work as normal, without disadvantage, when performed as a reaction through war caster?

It depends on the spell. Some spells require a melee attack but have a range longer than 5' (Thorn whip for example). BB and GFB in particular would require Spell Sniper and a weapon with enough reach, too.

Spells like Inflict Wounds and Shocking grasp would be unable to be used at all since the range is touch and iirc touch does not get extended by Spell Sniper.

All ranged attack spells would not have disadvantage if the creature leaving was the only one in melee range.

And again, that's simply what i read from the RAW as is, with an unbiased look at it. If a DM is fine with having the same timing for AoOs, that's fine. It's even fine if it makes the disadvantage disappear because "the creature is doing something else and not cares about you".