[RPG] Would the Dimension Door spell trigger or bypass the Mental Prison spell


After failing the saving throw for mental prison, the target is subjected, among other things, to this:

If the target is moved out of the illusion, makes a melee attack
through it, or reaches any part of its body through it, the target
takes 10d10 psychic damage, and the spell ends. (XGtE 161)

If, while under this effect, the target casts dimension door, what would happen? Would it count as being "moved out of the illusion" by the spell? Would the illusion, being in their head, follow them? Would this be different if someone else casts dimension door on them?

Best Answer

What it means to "be moved" is not defined in the rules so it falls to the Standard English meaning; for me, teleporting would count as "being moved" by the spell and so will not bypass mental prison's damage

Note that "to move" is a rules-defined term meaning "to expend movement" 2, 3 but using this to equate "to be moved" with "to be forced to expend movement" is probably not a good idea, and isn't supported in the rules anywhere. Thus we fall back onto the standard English meaning of "to be moved".

There is further support that "to be moved" uses the standard English meaning as shown in the "Opportunity Attacks" section of the PHB:

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.

This shows that someone/something can move you without expending your movement/action/reaction which points towards "to be moved" as using the standard English meaning.

I personally would say that teleportation counts as being moved by the spell and thus you are "being moved" which means that mental prison's damage will occur.

Additionally a dictionary definition of "move" (from lexico) defines it as:

1 Go in a specified direction or manner; change position.

When one teleports one has certainly changed position, and thus they have moved. It's up to a GM to decide whether something (the caster or the spell) has actually moved them. But in my opinion if something moves, something must have moved it. So regardless of how you've exited the area you have been moved out of it or moved through it and thus will take the damage.

Another option for dimension door is as follows:

[...] You can bring along objects as long as their weight doesn't exceed what you can carry. You can also bring one willing creature of your size or smaller who is carrying gear up to its carrying capacity. The creature must be within 5 feet of you when you cast this spell [...]

In this situation I would say the spell is still moving the chosen creature and so it will also not circumvent mental prison's damage. In fact, in this situation you could even say the caster is moving the chosen creature as well, so there's even more of a case for the creature having "been moved".

2: "Can you teleport closer to a creature you are Frightened of?
3: "Does teleportation count as movement for a Tabaxi's Feline Agility trait?"