repelling blast question

[OldSchoolDM]

If eldrtich blast (repelling blast) pushes an opponent how do you handle collisions? IE what happens if you push them when there is another enemy directly behind them? What about a terrain feature? Can the enemy behind use a reaction to displace to an empty square if able? What if unable?

[JNAProductions]

If eldrtich blast (repelling blast) pushes an opponent how do you handle collisions? IE what happens if you push them when there is another enemy directly behind them? What about a terrain feature? Can the enemy behind use a reaction to displace to an empty square if able? What if unable?

By RAW, if there's a wall, they hit the wall for no extra damage and stop moving.
Another creature, they'd either be pushed past them (if there's enough movement) or stop just before them-again, no extra damage.

You'd need something like a cliff, pit, wall of fire... Something like that to get extra damage.

And I agree with the RAW-Eldritch Blast with Invocations is quite powerful as it is. No need to make it more powerful by adding extra bits and bobs.

[Greywander]

Does fall damage apply if you fall sideways?

I have memories of playing the Dark Forces/Jedi Knight series as a kid and using cheats to fly around the map. While flying, you can build up ridiculous speed. And yes, if you run into a wall, you will take fall damage and die. IIRC, you could also use force powers like Force Push to deal damage if you pushed an enemy into a wall, possibly using the same fall damage physics.

[Zhorn]

I generally agree with JNAProductions on this that for RAW this does not require special rules as Eldritch Blast + Repelling Blast is pretty strong as is and does not NEED a boost. The wording on repelling blast saying 'up to 10 feet' is a pretty clear indication that it can stop short of that movement if obstructed ...

... BUT if I were to make a table ruling for the fun of it, I'd go with a fall damage and collision equivalent such as Greywander is suggesting. Each 10 ft of repelling movement that is interrupted by a solid object or creature is creature is treated the same way fall damage is calculated.
For collision damage, I'm partial to repurposing the rules for Fling used by the Kraken in the Monster Manual, or by giants in Storm King's Thunder, when the secondary creature makes a Dex save to dodge the repelled creature or take the same 'fall' damage.

It does buff the power of the Eldritch Blast + Repelling Blast combo, but it also encourages players to position themselves tactically to perform this maneuver as opposed to just standing stock still in combat.

[Man_Over_Game]

What I like to do is have collision damage equal to 1d4 for 5ft, and then increases in size for every additional 5ft.

So if you Thunderwave someone 10 feet back, but they are against a wall, they take 1d6 additional bludgeoning damage.

For the sake of Eldritch Blast, I'd probably rule that all movement-based damage is calculated after the spell ends. So if you knock an enemy back 4 times, he takes 1d10 damage instead of 4d4.

[Seclora]

Targeting particularly stupid creatures(Ex, Zombies), I sometimes allow collision, with a dex save vs falling prone. Generally though, I assume the other creature is able to dodge out of the way, moving closer if necessary to avoid sharing a space.

However, if the target is mounted, I make a Ride/Animal Handling check in order to stay mounted, moving both if they succeed, or just the rider if they fail. It doesn't come up very often, but it helps make the fight a little more dynamic.

[SpanielBear]

Our DM has never added extra damage unless the enemy falls from a significant height, but he occasionally makes them take an acrobatics check or fall probe if they are pushed over an obstacle, like off a low edge or flight of stairs. That’s still very nasty.

[Greywander]

However, if the target is mounted, I make a Ride/Animal Handling check in order to stay mounted, moving both if they succeed, or just the rider if they fail. It doesn't come up very often, but it helps make the fight a little more dynamic.
PHB page 198, under Mounting and Dismounting, it has rules for forced movement causing you to fall off. Seems like it only happens if it's your mount being moved, though, not you. Not sure what's supposed to happen if you get force-moved.

[Chronos]

It definitely shouldn't work like falling damage, because it's limited in how far it can push someone. Consider the simple case of a single blast pushing someone 10 feet. If there's a wall 11 feet behind them, they won't hit the wall at all, because they didn't get pushed that far. At 10 feet, they stop. If it behaves in any way resembling physics, then at 9', they're already slowing down and almost stopped. Assuming that the acceleration and deceleration are symmetric (and really, we have no reason to assume this), the creature would be at maximum speed halfway through the movement.

And of course, if it doesn't behave in any way resembling physics (and it might not; after all, it's magic, and it has weirdnesses like working equally on any creature size, and not working on inanimate objects), then we have no basis for extrapolating any behavior beyond what the book says.

[Rukelnikov]

We do collision damage like falling damage. So the enemy must have been moved at leas 10 ft. and hit a wall, its rare to be able to get the extra damage from collision more than once per enemy, since once they hit the wall they can't be moved 10 ft in order to trigger the collision again.

Also remember the world is 3d, even if you are on a grid, hiting someone from below will lift them up making them take falling damage afterwards.

[Lunali]

If you're going to do a knockback to falling damage conversion, do it based on the amount that they didn't get to move rather than how far they did. So if you knock someone back 30 feet (not particularly reasonable, but good for examples) and they hit a wall after 10, they'll take 2d6 falling damage.

[Zhorn]

If you're going to do a knockback to falling damage conversion, do it based on the amount that they didn't get to move rather than how far they did. So if you knock someone back 30 feet (not particularly reasonable, but good for examples) and they hit a wall after 10, they'll take 2d6 falling damage.

that's some fair reasoning

[Vogie]

If you're going to do a knockback to falling damage conversion, do it based on the amount that they didn't get to move rather than how far they did. So if you knock someone back 30 feet (not particularly reasonable, but good for examples) and they hit a wall after 10, they'll take 2d6 falling damage.

That may not be a good idea universally - Something like Gust of Wind would then be a damage dealing spell repeatedly, provided there is a wall you're pushing them against.

[Spiritchaser]

I would not even consider horizontal fall damage and would only assess collision damage if the thing the target was repelled into was prolifically sharp and spiky in its own right. So far this has happened exactly never at my table.

Repelling people into pits and chasms, off of cliffs, into spell effects or even just on to difficult terrain is plenty powerful enough.

[Lunali]

That may not be a good idea universally - Something like Gust of Wind would then be a damage dealing spell repeatedly, provided there is a wall you're pushing them against.

Str save or take 1d6 on a 2nd level spell isn't something I'd be overly worried about.