what can Major Image do

[Skrum]

I'm sure this has been asked before, but since it just came up in a game, I wanna get y'all opinions. I'm pretty sure illusions are very dependent on DM's rulings, and there isn't a hard or fast rule about what they can actually do or how other creatures react to it.

But, I guess I'm looking for a show of hands on a few particular uses. Assume we're talking about Major Image

- The spell says touching it reveals it to be an illusion, since physical objects pass right through it.....but what if you make an illusion of something that should be incorporeal, like a ghost? Is the magic still broken?

- Can Major Image recreate the effects of Fog Cloud or Darkness? Logic says yes, I think?

[No brains]

With the advent of Tasha's Summon Beast Spirit spell, Major Image can now be used as a bluff for a summoning spell. In the past, there was always a level of meta to the bluff of summoning a creature. It's reasonable to expect some enemy (or PC) to be too weak to actually summon a monster, but now there's plausibility to the deception.

Although it still isn't a great strategy. If you summon a creature and an enemy believes it to be a threat, its best solutions is to either attack the creature or the summoner. Major Image won't make you any safer against an enemy willing to take a risk.

One could argue it can alleviate stress from heat or cold. It depends on how 'real' the DM wants the heat it radiates to be, but the only listed limitation is that it can't deal damage. Alternately, you could use it to turn up the heat on someone you're interrogating. If the heat is real enough to cause exhaustion, it would be worth it to give disadvantage to deception checks.

[Segev]

I would argue that it definitely can feel like a fire from a reasonable distance, but touching an illusory fire definitely reveals it as it isn't painfully hot. Technically, it only "goes faint" visibly, IIRC, if revealed, so other sensory inputs remain the same, but you could also argue/rule that all of the sensory aspects "go faint" in some fashion that lets you sense the underlying reality. That said, somebody fooled by the illusory fire's warmth would still freeze in the genuine cold, even as he might wonder why he can't get warm. ...though, reading the spell, it actually doesn't say the temperature is "fake," only that it can't do damage. Interesting. So maybe it can keep you warm, or cool you comfortably. Ask your DM.

It does affect all senses, though, so it should work on any blindsight or tremorsense, too. And, if you are able to cast it from a sixth level slot and have malleable illusions, it becomes the every-illusion for you. Keep it in sight and you can change it to anything you like as an action, no casting required!

[Psyren]

- The spell says touching it reveals it to be an illusion, since physical objects pass right through it.....but what if you make an illusion of something that should be incorporeal, like a ghost? Is the magic still broken?

1) As written, yes, you'll know. It doesn't matter what the illusion is depicting, physical interaction reveals it for what it is.

2) Technically ghosts aren't "incorporeal" in 5e because nothing is. They and most undead (or other creatures) that were "incorporeal" in prior editions have at least some degree of tangibility* in 5e, because they can be hurt by nonmagical physical attacks and are slowed down when moving through solid objects and creatures.

*while on the Material plane


- Can Major Image recreate the effects of Fog Cloud or Darkness? Logic says yes, I think?

Yes and no. Like making an illusion of a wall, an illusion of fog or darkness will obscure anything behind it and likely hide it from passive observation. If the character is actively searching however, they will most likely trigger the Investigation check needed to defeat it.

[Segev]

1) As written, yes, you'll know. It doesn't matter what the illusion is depicting, physical interaction reveals it for what it is.

2) Technically ghosts aren't "incorporeal" in 5e because nothing is. They and most undead (or other creatures) that were "incorporeal" in prior editions have at least some degree of tangibility* in 5e, because they can be hurt by nonmagical physical attacks and are slowed down when moving through solid objects and creatures.

*while on the Material plane



Yes and no. Like making an illusion of a wall, an illusion of fog or darkness will obscure anything behind it and likely hide it from passive observation. If the character is actively searching however, they will most likely trigger the Investigation check needed to defeat it.

All accurate to the RAW.

I would, however, argue on a "rulings, not rules" level that a DM can - even should - consider ruling that, if the illusion is of something you wouldn't feel if you touched it, you should not automatically pierce it if you DO touch it. Particularly with major image, which is higher-level than any of the effects in question that you could cast with other spells. (Silent image runs into a natural problem with emulating fog cloud by both having a smaller area and by lacking the tactile "feel" of fog. Not 100% noticeable, but still a valid thing to bring up as a concern.)

[JLandan]

There was a big old thread on this very thing a while back.

This came up while I was DM. An Illusionist used MI to create a fog to obscure the party's movement past a guard post (A 3rd level spell, when, mind you, he HAD Fog Cloud, a 1st level spell). The other players pointed out that the 1st level spell would work perfectly, while the 3rd level spell ran the risk of discovery. I guess he was illusion spell crazy.

I didn't want to just burst his bubble, so I gave the guards (orcs) a wisdom save. They failed, so I allowed the ploy to work.

In the case of an incorporeal creature, I would probably do the same. Maybe with a really low DC because it wouldn't take much to realize that the "wraith" isn't attacking anybody. A behavior one doesn't often see in incorporeal undead.

[Segev]

There was a big old thread on this very thing a while back.

This came up while I was DM. An Illusionist used MI to create a fog to obscure the party's movement past a guard post (A 3rd level spell, when, mind you, he HAD Fog Cloud, a 1st level spell). The other players pointed out that the 1st level spell would work perfectly, while the 3rd level spell ran the risk of discovery. I guess he was illusion spell crazy.

I didn't want to just burst his bubble, so I gave the guards (orcs) a wisdom save. They failed, so I allowed the ploy to work.

In the case of an incorporeal creature, I would probably do the same. Maybe with a really low DC because it wouldn't take much to realize that the "wraith" isn't attacking anybody. A behavior one doesn't often see in incorporeal undead.

The big advantage to using an illusion instead of real fog cloud is that you can TELL your allies it's an illusion, and they can knowingly and intentionally make the Investigation check, then, to get the ability to see through it, while your enemies cannot see through it.

[Psyren]

I would, however, argue on a "rulings, not rules" level that a DM can - even should - consider ruling that, if the illusion is of something you wouldn't feel if you touched it, you should not automatically pierce it if you DO touch it. Particularly with major image, which is higher-level than any of the effects in question that you could cast with other spells. (Silent image runs into a natural problem with emulating fog cloud by both having a smaller area and by lacking the tactile "feel" of fog. Not 100% noticeable, but still a valid thing to bring up as a concern.)

Even putting RAW aside, I don't think tangibility of the thing being depicted should necessarily matter either. Sure, you can't "feel" a fog when you swing your sword through it, but real fog still reacts a certain way to that physical interaction that I think would be beyond Major Image's intended (and actual) programming, which is part of the reason for the automatic success. Furthermore, as mentioned, "incorporeal" undead are even worse since they must have some degree of tangibility for them to work the way they do, the absence of which would give them away (again, both by RAW and RAI).

At most I would consider some kind of disadvantage on the revelatory check if you depict something particularly congruous (and, by corollary, advantage if you go with something difficult to believe like a massive golem on a rickety/rotten wooden platform etc.)


The big advantage to using an illusion instead of real fog cloud is that you can TELL your allies it's an illusion, and they can knowingly and intentionally make the Investigation check, then, to get the ability to see through it, while your enemies cannot see through it.

I'd say that asymmetrical benefit would last right up until the first time your allies make an attack through the fog that indicates they can see the enemy clearly. Reason enough for the enemy to (intelligently) have a chance at concluding that the "fog" or "darkness" the shots are accurately coming from may not be real. Mindless or extremely dumb enemies of course would either automatically or likely fail the check in question.

[Segev]

Even putting RAW aside, I don't think tangibility of the thing being depicted should necessarily matter either. Sure, you can't "feel" a fog when you swing your sword through it, but real fog still reacts a certain way to that physical interaction that I think would be beyond Major Image's intended (and actual) programming, which is part of the reason for the automatic success. Furthermore, as mentioned, "incorporeal" undead are even worse since they must have some degree of tangibility for them to work the way they do, the absence of which would give them away (again, both by RAW and RAI).

At most I would consider some kind of disadvantage on the revelatory check if you depict something particularly congruous (and, by corollary, advantage if you go with something difficult to believe like a massive golem on a rickety/rotten wooden platform etc.)I don't want to derail, so I will simply say that I disagree with the assertion that fog will visibly react to motion through it. In practice, this will always be a DM's call; no "settled consensus" is likely.


I'd say that asymmetrical benefit would last right up until the first time your allies make an attack through the fog that indicates they can see the enemy clearly. Reason enough for the enemy to (intelligently) have a chance at concluding that the "fog" or "darkness" the shots are accurately coming from may not be real. Mindless or extremely dumb enemies of course would either automatically or likely fail the check in question.
Potentially. Certainly, excuse enough to take the action to make the Investigation check, at the least.

[Psyren]

I don't want to derail, so I will simply say that I disagree with the assertion that fog will visibly react to motion through it. In practice, this will always be a DM's call; no "settled consensus" is likely.

Fair enough, but the RAW that an image of fog will get revealed by physical interaction just like an image of a solid remains.

[Chronos]

Personally, I rule that interaction with an illusion reveals it if the interaction is of a sort that makes it obvious that it's not what it appears to be. If you throw a rock at a brick wall and it goes through, that's not something that real brick walls can do at all, so it's obviously fake. If you throw a rock at a cloud of fog and it goes through, well, that's how real fog acts, so it doesn't reveal. The illusion of a cloud probably doesn't react exactly the same as a real cloud, but that's what an investigation check is for, and if you're not making the effort to investigate in detail (i.e., taking your action to do so), then it's close enough.

[Segev]

Personally, I rule that interaction with an illusion reveals it if the interaction is of a sort that makes it obvious that it's not what it appears to be. If you throw a rock at a brick wall and it goes through, that's not something that real brick walls can do at all, so it's obviously fake. If you throw a rock at a cloud of fog and it goes through, well, that's how real fog acts, so it doesn't reveal. The illusion of a cloud probably doesn't react exactly the same as a real cloud, but that's what an investigation check is for, and if you're not making the effort to investigate in detail (i.e., taking your action to do so), then it's close enough.

I generally agree with this.

However, as a matter of discussion, what happens if you throw an illusory rock at a real wall? That is to say: why is it you KNOW upon seeing a rock fly through a wall that it is the wall that did something impossible?

in the end, it's best to stick, I think, with what you've outlined in what I've quoted, but I still think it bears some thinking about. If a ghost walks through a wall, nobody bats an eye (other than to be afraid of the ghost, perhaps). If a seemingly-solid human walks through a wall, one might think that the "human" was a ghost, after all, or that the wall is an illusion. Or that the "human" was an illusion. Without the "it's automatically revealed" bit, how would you know just from watching?

Ultimately, it's all going to come down to discussion and negotiation with your DM, because illusions are one of those things that are easily rendered useless if the DM's rulings aren't very careful, but also can become stupidly overpowered if the DM is too generous. And it's a lot of cognitive load to have to separate the DM's knowledge that an illusion is fake from the NPCs' perceptions, especially when the DM doesn't necessarily know what the player was expecting the NPCs' reactions to be. Illusions tend to be much stronger in the DM's hands because the players are used to taking anything the DM says as part of description at face value.

"The wizard waves his arms and a demon appears in a puff of smoke!" is hardly cause for players to immediately assume it's an illusion. But it can be difficult, when the DM knows that demon isn't real, to have his monsters react to it as if it were. Would they really attack it, or would they run away? Would they really run away, or would they ignore it and go after the softer targets? It's a tough judgment call when the DM has to try to put himself in the hypothetical scenario where the illusion IS real and decide what his monsters would do, and also has to double-check himself that he's not looking for excuses to launder the information he has to the monsters' knowledge.