Mirage Arcane

[dejarnjc]

Quick question regarding this spell. Could I use this in a city to make a castle or a tower? Alternatively, could I use the spell to make illusory walls around a city?

[Asmotherion]

Ofcourse you can. You can add structures where non are present, turn clear ground into difficult terrain or vice versa... The illusion you make is almost perfect, with only one exception; it cannot produce any taste.

It is otherwise interacted with as if the things contained in the illusion were real.

[dejarnjc]

Interesting, so I guess the real risk in using it for city defense would be that a dispel magic would take it down

[Flashy]

As Asmotherion said, but with the additional note that the spell can only cover a square mile so any city you want to surround with walls needs to be smaller than that.

[sambojin]

Is pool of lava or erupting volcano a terrain? And would that cause damage due to such interactions with it? Can things drown or swim in an illusory lake, or is it just difficult terrain to walk through (even though is looks like you're walking along the bottom of a lake-bed to you)?

Is this just a DM decides question?

[Tanarii]

It is otherwise interacted with as if the things contained in the illusion were real.Specifically, it says "The Illusion includes audible, visual, tactile, and olfactory elements, so it can turn clear ground into difficult terrain (or vice versa) or otherwise impede Movement through the area."

Turning terrain to difficult terrain, not-difficult terrain, or impeding movement is a little more limited than completely interacting as if it were real. For example, there's no indication you could put a 500ft tall hill over your city, and creatures could literally ride up into the air and over it, descending to the other side. OTOH that's probably not necessary to spell out, since "The terrain's general shape remains the same". But the impeding movement clause would be sufficient for an added illusionary curtain wall to prevent enemies from getting past.

All this is basically mental rambling after I went to look up the spell to make sure it had the Intelligence (Investigation) check to bypass said illusionary curtain wall. And went into shock on discovering it didn't. That makes it pretty powerful.


Is pool of lava or erupting volcano a terrain? And would that cause damage due to such interactions with it? Can things drown or swim in an illusory lake, or is it just difficult terrain to walk through (even though is looks like you're walking along the bottom of a lake-bed to you)?

Is this just a DM decides question?
IMO as a DM, yes, no because damage is not adding/removing difficult terrain or impeding movement, and no things can't drown because its not adding/removing difficult terrain or impeding movement. All answers predicated on having just read the spell again right now and never having had a player use it in one of my games before, so off the cuff.

I'm interested to hear what other DMs would rule off the cuff, or have actually ruled in games.

[Chaosmancer]

I had an enemy boss use this. It was a hybrid Aboleth/Beholder using Volo's alternative main eye.

I probably over-powered the effect, essentially using it to add a dry room to the creature's acid pool lair. Since the room was an illusion and Mirage Arcane allows for changes as an action, it did things like open windows for it to shoot thru, turn the floor into spikes, create columns to shove creatures into.

Essentially it gave me an excuse to manipulate that room and therefore the battfield in unexpected ways. I didn't abuse it by turning the floor to lava or even dealing much damage, but then again, two members of the seven member team rushed ahead and kicked down the door, so it wasn't exactly a fair or even balanced encounter anyways.

I'd be interested in seeing a player using the spell, because it does seem incredibly powerful to manipulate a battlefield like that

[Luppers]

I had an enemy boss use this. It was a hybrid Aboleth/Beholder using Volo's alternative main eye.

I probably over-powered the effect, essentially using it to add a dry room to the creature's acid pool lair. Since the room was an illusion and Mirage Arcane allows for changes as an action, it did things like open windows for it to shoot thru, turn the floor into spikes, create columns to shove creatures into.


Mirage arcane doesn't allow you to change the illusion once cast.

Were you thinking of malleable illusions from the wizard illusion subclass?

[Chaosmancer]

Mirage arcane doesn't allow you to change the illusion once cast.

Were you thinking of malleable illusions from the wizard illusion subclass?

No i wasn't... Reading it again... Huh. I guess i read all those "you can change" parts as being continuous instead of just once.

Was it Volo's that led me to think that...it doesn't specify, but i think because it was connected to the main eye I jumped to a conclusion about its effects. Well, glad i caught that, though it does make using that similar tactic harder to justify in the future... Dang.

[Asmotherion]

Specifically, it says "The Illusion includes audible, visual, tactile, and olfactory elements, so it can turn clear ground into difficult terrain (or vice versa) or otherwise impede Movement through the area."

Turning terrain to difficult terrain, not-difficult terrain, or impeding movement is a little more limited than completely interacting as if it were real. For example, there's no indication you could put a 500ft tall hill over your city, and creatures could literally ride up into the air and over it, descending to the other side. OTOH that's probably not necessary to spell out, since "The terrain's general shape remains the same". But the impeding movement clause would be sufficient for an added illusionary curtain wall to prevent enemies from getting past.

All this is basically mental rambling after I went to look up the spell to make sure it had the Intelligence (Investigation) check to bypass said illusionary curtain wall. And went into shock on discovering it didn't. That makes it pretty powerful.


IMO as a DM, yes, no because damage is not adding/removing difficult terrain or impeding movement, and no things can't drown because its not adding/removing difficult terrain or impeding movement. All answers predicated on having just read the spell again right now and never having had a player use it in one of my games before, so off the cuff.

I'm interested to hear what other DMs would rule off the cuff, or have actually ruled in games.

I was under the same impression, and when I realised it didn't I had the same reaction.

As a dm, I kinda let it interact as per 3.5 "Shadow Magic" in that the effects are partially real. The important parts for me being:

-It can add structures were non are present.
-It can create difficult terain on clear terain or vice verca
-It includes tactile (and other sences, except taste) sensory effects that can be interacted with.

Overall, if you made a bridge, you would pass safelly from it without any problem. However, (and this is strictly my own house rules), if you were to take any form of damage directly from an element created from the illusion, it would be psychic damage (for ecample, being pushed into an illusionary campfire), since the fire is not real. I would make the damage significantly smaller (d4), and leave no actual burn after a few minutes, wich would allow someone an investigation check to at least understand they are into an Illusion.