D&D 5E How does the Phantasmal Force spell work correctly?

[lkwpeter]

I found several interesting posts from Jeremy Crawford:

Object moving with target: Jeremy Crawford approved that the created object moves with the target.
http://www.sageadvice.eu/2015/09/14/phantasmal-force-on-a-bag/

Fighting creature moving: Analogous to that I would rule that if you create an hostile creature that is attacking the target, this creature would not be bound within the 10 foot are of the spell. It would follow the target, if that is trying to escape, because the creature is within the target's mind. Consider that the "conjured" creature must be not larger than 10 foot, but not the area that it is able to move, etc.

Creating Phenomena: Also it seems possible to create phenomena with Phatasmal Force. So, you could argue that an burning object consists of two things: object + fire. That's what the DM has to decice. For me as a DM, it would be okay, if you want to create a glowing cage.
http://www.sageadvice.eu/2015/09/14/blinding-phantasmal-force/

 

[gyor]

Cool uses for Phantasmal Force

Divine Intervention, create an illusionary manifestation of the target's God or Gods, including both a visible element and the voice of that God, keyed to that god's mythology and symbolism. Can include some kind of punishment is painful. Profiency in the Religion skill an asset.

Drugs- create the illusion of a drug the target takes and it's effects, could be good as a bribe, something to sell, a distraction.

A poison mist- a more violent version of the above.

Sex- good as a distraction, to make some gold, to have some fun, to seduce someone into compliance, and if you want it kinky you can even have it deal damage.

Fire in a blizzard- The target believes it started a warm fire, but it didn't then it dies of cold eventually, believing it's warm.

Healing potion- Target drinks it, believing itself healed while it bleeds out.

Magical item- if you give them 100gp you can have this magic sword, see feels it magical power buzzing through your arm as you weild it.

Secret message- You appear before the target with words for it's ears only.

Sword Grubs- a monstrous grub bursts from the handle of the targets sword biting it.

Glyphs of Warding- the target sets off an illusionary Glyph Warding.

 

[Saeviomagy]

You sure you responded to the right post?

Yup

I am saying exactly what you are saying: that the target doesn't get anywhere without disbelieving.

Nope, I was saying...

I made my comment as a response to somebody saying you could attempt a "break chains" strength check, and when you realized your arms moved (since there aren't any real chains), you automatically made your strength check and was free of the phantasmal force.

Is that.

The illusion can't actually stop an application of force. You can move your arms fine if you choose to, so the illusion had to change to make sense. The chains break and you are free.

 

[lkwpeter]

The illusion can't actually stop an application of force. You can move your arms fine if you choose to, so the illusion had to change to make sense. The chains break and you are free.

I agree. I think, if the spell would create objects that affect creatures physically, it would just be too powerful and have big intersections with other spells.

So, I believe the best way to consider, whether a specific object created with Phantasmal Force would be viable or not, is to apply the following rule of thumb:

• "Is the object supposed to physically affect a creature?" If yes, the effect is not possible.
• "Is the object supposed to only affect the creature's motivation to do something?" If yes, than it is absolutely viable and works as the spell is intended to work.

 

[CapnZapp]

The illusion can't actually stop an application of force. You can move your arms fine if you choose to, so the illusion had to change to make sense. The chains break and you are free.

If you mean, you rule that you can't use the spell to apply force, sure, go right ahead.

If , however, you're talking about circumventing the Investigate check, I'm not cool with that.

As you might have surmised from my participation in the thread, the spell certainly doesn't need any more freedoms than it's already got. And I'm there for you when you want to smack down overpowered usages of a mere level 2 spell.

But in this specific instance, I can't agree. Making Strength tests? Automatically succeeding at them? That's something you've added - that is not part of the spell as written.

The only way to get rid of the spell is by making an Investigation check. Much of the discussion revolves around ways to not trigger that check for the target, to prolong the effects. Which is fine by me... as long as the target isn't affected by any status conditions in the meanwhile.

If the spell can slap debilitating status conditions on you, and you're not even allowed to investigate... yeah, well, that's cheesy as hell. I don't care how well you've crafted your illusion - overpowered is overpowered, and the spell is already strong as it is for a level 2 spell.

Regards

 

[lkwpeter]

If the spell can slap debilitating status conditions on you, and you're not even allowed to investigate... yeah, well, that's cheesy as hell. I don't care how well you've crafted your illusion - overpowered is overpowered, and the spell is already strong as it is for a level 2 spell.

Well, I might misunderstand your words because of language issues, but I think that some status effects (e.g. blinded) are indeed possible to be triggered under certain circumstances. Jeremy Crawford said that it would be possible, if you "describe an illusory visible phenomenon that douses the light". (see Jeremy's Tweet)

 

[CapnZapp]

Well, I might misunderstand your words because of language issues, but I think that some status effects (e.g. blinded) are indeed possible to be triggered under certain circumstances. Jeremy Crawford said that it would be possible, if you "describe an illusory visible phenomenon that douses the light". (see Jeremy's Tweet)

Thanks. Yes I am aware.

If you allow status effects, I would be sure to also allow the target its check each round.

That really is all. I understand people finding much joy in coming up with clever illusions that doesn't make the target go investigate, but in a combat context that's just broken.

 

[lkwpeter]

Original Post:

1.) I read a lot about "casting a black container around a creature's head" so that the creature is blinded. Or "casting some loud noises to it's ears, so it is deafend". But is that really possible?

2.) Also I would like to know, how creatures act that I cast. For example if I want to make a hostile creature beliefe that his boss is talking to him and wants it to leave his guard post. Can I interact with the illusion or change things after I cast it?

3.) What other restrictions are there? And what is the best use of it?

EDIT: The following is a personal summary of this forum thread:

Please note, that I don't claim this to be the only way of interpreting the rules. Phantasmal Force is very vague and this thread was a try to find an interpretation that is consistent with the wording of the RAW and that is consistent in analogy to other spells. These are just the main agreements of this discussion:


Effects:

• If you create a person, you do not need to know the language/appearance of the it. Like I'm a Banana said, "It's not like the illusionist is making the illusion say something, it's like the illusionist is saying, "get this concept across" and the target's mind shows the target what the concept would look like from the target's perspective. So, it relies on the target's sense of what's possible, not the illusionist's. That's part of why they're just single-target.". Furthermore this is not part of the spell's description, although some other spells explicitly say so.
• You can also create phenomena. And those can even cause status effects (e.g. blinded). (see Jeremy Crawford's Tweet here)
• Like Jeremy Crawford approved, created objects will move with the target and can also cause status effects (see his Tweet here).
• Analogous to that, if you create a hostile creature that is attacking the target, this creature would not be bound to its position. Instead, it would also follow the target, if that is trying to escape, etc. The reason is, that the creature is within the target's mind, so it won't be stuck to a position. Consider that only the "conjured" creature must be not larger than 10 foot, but not the area that it is able to move within.
• Physical interactions do NOT reveal the illusion! The reason again is that the illusion is within the target's mind. That is very different to other illusion spells.

Restrictions:

• The object must be visible for the target (spell description). So it can't be invisible.
• If the illusion is not reasonable to the target, it will probably investigate it. Consider, that illusions that look like magical spell effects are hardly "not reasonable", because the target would normally think that it's a "normal" spell effect. Contrary to this, if the target's mom that has died years ago suddenly appears in front of it, the target would probably "resist" the illusion and investigate it (as an action, after it failed the initial INT saving throw).
• After casting this spell, there is no further interaction with the illusion possible: Like Storyteller Hero said, "the phantasm can act as you "pre-program" it." The caster can neither see the illusion himself, nor can he change or interact with it after he casted the spell.

Controlling creatures (shackles, cages, etc.):

• The most important point is: This spell is a psychic force, no physic force! So, it is not possible to physically control a creature! If you create chains to bind it, these might even move a bit with the target. But the moment, the target moves away from the object, its arms/legs would simply go through the illusion. The creature would rationalize it in some way (as the spell description says), but it would be free though.
• Instead, you could try to affect the creature's motivation to do something: E.g. you could create a cage of fire. The creature might feel the heat an decide not to touch it. Or you could create something that forces the target to go prone at its own will (e.g. a poisonous fog at a specific height, so that the could duck).
• Apply the following rule of thumb to find out, whether or not a specific object would work to control a creature:
  1.) "Is the object supposed to physically affect a creature?" If yes, the effect is not possible
  2.) "Is the object supposed to only affect the creature's motivation to do something?" If yes, than it is absolutely viable and works as the spell is intended to work.

When does Phatasmal Force allow a INT (Investigation) check?

This is tough question, because the spell's description says: "The target rationalizes any illogical outcomes from interacting with the phantasm." That means two things:

1. The target rationalizes everything from interacting with the phantasm (and only with the phantasm).
2. The target rationalizes inconsistencies only from interacting.

For this reason, external influences could be one reason that raises doubts. But keep in mind that other creatures don't see the illusion!

 

[Saeviomagy]

If you mean, you rule that you can't use the spell to apply force, sure, go right ahead.

That's a given.

If , however, you're talking about circumventing the Investigate check, I'm not cool with that.

Why not? The spell says the target rationalizes any inconsistent interactions: since the spell can't exert force, it cant resist an attempt to break the chains, so you've got an inconsistent result. It's resolved by the target breaking free.

As you might have surmised from my participation in the thread, the spell certainly doesn't need any more freedoms than it's already got. And I'm there for you when you want to smack down overpowered usages of a mere level 2 spell.

But in this specific instance, I can't agree. Making Strength tests? Automatically succeeding at them? That's something you've added - that is not part of the spell as written.

See above. The spell can't exert any force. How is it going to hold the target still?

It's the downside of using an incredibly potent and versatile spell instead of a spell that has a single and very limited use: hold person. If phantasmal force isn't breakable as I describe, then it's a flat-out better spell in every conceivable way by a massive margin: it targets a resistance most monsters don't have, it can inflict almost any combination of statuses you want, it can affect a much wider range of foes, it can deal damage, it requires an action to break and it has utility applications.

The only way to get rid of the spell is by making an Investigation check. Much of the discussion revolves around ways to not trigger that check for the target, to prolong the effects. Which is fine by me... as long as the target isn't affected by any status conditions in the meanwhile.

The only way to get rid of the spell, sure. But not the only way to not be restrained by it.

If the spell can slap debilitating status conditions on you, and you're not even allowed to investigate... yeah, well, that's cheesy as hell. I don't care how well you've crafted your illusion - overpowered is overpowered, and the spell is already strong as it is for a level 2 spell.

I don't see how you would ever 'not be allowed to investigate'. I can see situations where a creature may decide not to investigate. The flip side of that is that there are creatures who will simply brute force their way out, and the illusion cannot stop them from doing that.

 

[transtemporal]

One question I have is: can you make the subject of a phantasmal force understand something it doesn't already know? Like can I plonk manacles on someone and say "they're anti-magic manacles!" - if the illusion is created by the subjects mind, how do they know what anti-magic manacles are?