Can't end your movement in another creature's space - but what if you do?

[Monster Manuel]

The rules are clear that you can't willingly end your movement in another creature's space, but if circumstances arise where you wind up in another creature's space anyway, they are less clear about what happens then.

Is there some official rule in any of the main books that describes this scenario? Or is it basically just DM fiat? How have you handled this when it comes up?

[Aett_Thorn]

What circumstances would cause this? Voluntary movement is controlled by the player, and they can’t move into the space of another creature if they would end their movement there. And anything else would be involuntary movement, right?

[heavyfuel]

The rules are clear that you can't willingly end your movement in another creature's space, but if circumstances arise where you wind up in another creature's space anyway, they are less clear about what happens then.

Is there some official rule in any of the main books that describes this scenario? Or is it basically just DM fiat? How have you handled this when it comes up?

Pretty sure it falls in DM Fiat. I'd rule you automatically end it in the closes available square.

[Keravath]

What circumstances would cause this? Voluntary movement is controlled by the player, and they can’t move into the space of another creature if they would end their movement there. And anything else would be involuntary movement, right?

Entering the square of a creature two sizes larger than you that also contains either caltrops or ball bearings which can end your movement or make you fall prone in which case you might not have sufficient movement to stand up and move to another square. In either case, your movement ends involuntarily in a square occupied by another creature.

What happens next it up to the DM but personally I'd rule that pretty much everything - attacking, defending, casting spells is unaffected.

[sithlordnergal]

What circumstances would cause this? Voluntary movement is controlled by the player, and they can’t move into the space of another creature if they would end their movement there. And anything else would be involuntary movement, right?

I could see it happening pretty easily. You have 30 movement, you spend 15 to get to a doorway with an ally and Grease spell in the way. You try to slip past your ally, spending 10 feet of movement to enter their space, putting you at 25 feet. But you slip due to Grease and fall prone. It costs 15 movement to stand up, because you need to spend half of your total movement to stand up from Prone, but you only have 5 feet left so you're stuck there.


At that point it is DM fiat. You've caused a thing to happen that technically isn't covered by the rules. Personally, I'd see how the players RP it and go from there.

Is the person who's standing trying to not step on their friend? Dex save or fall on top of each other, and disadvantage on the save against Grease if they don't move that turn. Are they standing on their friend? Disadvantage on attack rolls because of unstable footing, but they ignore the effects of Grease.

I'd probably have the prone person make some checks as well to avoid knocking their friend over.

[Lunali]

I could see it happening pretty easily. You have 30 movement, you spend 15 to get to a doorway with an ally and Grease spell in the way. You try to slip past your ally, spending 10 feet of movement to enter their space, putting you at 25 feet. But you slip due to Grease and fall prone. It costs 15 movement to stand up, because you need to spend half of your total movement to stand up from Prone, but you only have 5 feet left so you're stuck there.


At that point it is DM fiat. You've caused a thing to happen that technically isn't covered by the rules. Personally, I'd see how the players RP it and go from there.

Is the person who's standing trying to not step on their friend? Dex save or fall on top of each other, and disadvantage on the save against Grease if they don't move that turn. Are they standing on their friend? Disadvantage on attack rolls because of unstable footing, but they ignore the effects of Grease.

I'd probably have the prone person make some checks as well to avoid knocking their friend over.

If it were me, I'd probably just have them slide while prone an extra square both for comedic effect and to minimize the amount of thinking necessary.

[Narbaculus]

As a DM, I always treat moving through another creature's space, relative size notwithstanding, as squeezing, per page 192 of the PHB.

[Naanomi]

Halflings and invisible creatures?

[HappyDaze]

Treat like putting a bad of holding into a portable hole.

What?

If players want to make stupid happen, give them a triple helping. Besides, there's nothing in the rules to say that isn't what would happen.

[MaxWilson]

As a DM, I always treat moving through another creature's space, relative size notwithstanding, as squeezing, per page 192 of the PHB.

Elegant.

I would only not apply this penalty to the creature that was in the space originally, but it makes sense to apply it to every subsequent creature that enters the area.

[Naanomi]

Elegant.

I would only not apply this penalty to the creature that was in the space originally, but it makes sense to apply it to every subsequent creature that enters the area.
Presumably not Halflings for larger creatures?

[Crucius]

If it were to happen, as the DM I'd roll a d8 in the open, and the number dictates which adjacent square the player character is ejected to. This way no-one can game the system, as it is random, and you don't violate the rule that you cannot end your movement in another creature's space.

[Monster Manuel]

As a DM, I always treat moving through another creature's space, relative size notwithstanding, as squeezing, per page 192 of the PHB.

I like that, it's a fairly elegant solution to those situations when two creatures wind up in the same space (the scenarios I had in mind were moving through an ally's space and getting hit with a sentinel opportunity attack, dropping your move to 0 in the ally space. Also, multiple characters falling down a 5' wide mine shaft). You can't voluntarily do it, but there are times when it makes more sense to say "there's two of you in this space" than "you land 5 feet away, because there was already a dude standing there".

Using the squeezing rules to represent how awkward it is to maneuver when there's someone right on top of you works mechanically, and you don't have to invent something new. Thanks for that!

[MaxWilson]

Presumably not Halflings for larger creatures?

No, why would I make an exception for halflings?

[Naanomi]

No, why would I make an exception for halflings?
Because they have a racial ability to do so normally, so applying a penalty and granting eveyone else the ability equivalent to theirs seems like... taking away from them?

“Halfling Nimbleness. You can move through the space of any creature that is of a size larger than yours.”

[Narbaculus]

Presumably not Halflings for larger creatures?

Yes, of course. I should have mentioned that.

edit: Exceptions are made for Halfling Nimbleness, Gaseous Form, and other special circumstances.

[MaxWilson]

Because they have a racial ability to do so normally, so applying a penalty and granting eveyone else the ability equivalent to theirs seems like... taking away from them?

“Halfling Nimbleness. You can move through the space of any creature that is of a size larger than yours.”

But their racial ability doesn't affect anything related to squeezing. They still pay the difficult terrain penalty, take disadvantage in attack rolls, can't normally stop in an allied space, etc. Their racial ability is irrelevant to this thread.

[Laserlight]

Looks like you could fit 3-4 guys, possibly more, in a square in The Real World.

I might say each one gets cover from, and cannot attack into, three squares on the left or right -- ie Alice is on the left and Bob on the right, so Bob can't attack to the left and gets cover from attacks originating from the left because Alice is in the way. Missile fire that misses Bob might hit Alice. Might have disadvantage on DEX saves because of being crowded. All this assumes they're both standing, of course.

One other way you could get two people in one square is if one of them is dead. If you're moving through I'd probably say you get half movement or have to take a DEX roll with the possibility of falling; if you're just standing there, I wouldn't make you roll.

[MaxWilson]

Looks like you could fit 3-4 guys, possibly more, in a square in The Real World.

I might say each one gets cover from, and cannot attack into, three squares on the left or right -- ie Alice is on the left and Bob on the right, so Bob can't attack to the left and gets cover from attacks originating from the left because Alice is in the way. Missile fire that misses Bob might hit Alice. Might have disadvantage on DEX saves because of being crowded. All this assumes they're both standing, of course.

One other way you could get two people in one square is if one of them is dead. If you're moving through I'd probably say you get half movement or have to take a DEX roll with the possibility of falling; if you're just standing there, I wouldn't make you roll.

Another important time this could happen: you're hiding, and you don't want to give away your position by actively blocking the enemy from being within 5' of you. You'd rather just act like difficult terrain and hope he doesn't decide to randomly attack the difficult terrain.

[Lunali]

Another important time this could happen: you're hiding, and you don't want to give away your position by actively blocking the enemy from being within 5' of you. You'd rather just act like difficult terrain and hope he doesn't decide to randomly attack the difficult terrain.

I hope you mean a situation where you're invisible, otherwise hiding within a 5' square shared with an enemy is pretty unlikely. I mean, you're close enough that rather than being able to reach out and touch them, you have to actively avoid being touched by them.

[MaxWilson]

I hope you mean a situation where you're invisible, otherwise hiding within a 5' square shared with an enemy is pretty unlikely. I mean, you're close enough that rather than being able to reach out and touch them, you have to actively avoid being touched by them.

I was thinking of darkness. I don't think mere Invisibility would be enough--they'd be suspicious of the invisible difficult terrain.

[Chronos]

It can happen. Once, playing Capture the Flag at Scout camp after sunset, one guy managed to hide in tall grass so well that an opponent stepped on him without even realizing he was there.