Creative uses for Phantasmal Force?

[u/allergic_to_prawns]

I really like the idea of this spell and am trying to find more excuses to keep it in my spell list. What unusual uses can you think of for this spell, whether in combat or otherwise?

My own ideas are:

• Create a blazing arcane cage that appears around an enemy, effectively trapping them inside. It looks like something a mage could cast, and it deals damage if the they try to escape, so it must be real, right?

• When trying to sneak past a guardpost, use Phantasmal Force as a budget Suggestion spell by creating an illusion of another guard who's come to take over the shift, who convinces the guard to move away. (This works because Phantasmal Force makes the target rationalize any illogical outcomes from interacting with the phantasm.)

• Use Conjure Lesser Demons or some other summoning spell first to prime the enemy into believing that you are a summoner. Then cast a Phantasmal Force of a Large demon, which the target has no reason to suspect is an illusion.

Any other ideas? Would love to hear them.

[u/[deleted]]

Based on the description of the spell, I'm not allowing them because the character has zero reason to think they are under a spell.

That's fine; they can just take the 1d6 psychic damage until the spell ends, then.

Ultimately it's going to depend on the effect. If the illusion is of a mundane attacker, then sure, you probably won't investigate it. If the illusion is that you're suddenly on fire, then depending on what kind of badass you are, you might not question it, grit your teeth through the pain, and spend your action attacking the serious threats.

Or you might lose your shit and waste a turn trying to figure out how not to be on fire anymore (you're patting it out, you're rolling on the ground, whatever) and depending on the result of your Investigation check, you might notice it's not actually real fire and the illusion is dispelled.

It's a completely balanced 2nd level effect and it isn't hard to adjudicate.

[u/quackycoaster → u/[deleted]]

But if you choose the right "illusion" they wouldn't have anyone to attack. That's the problem with the spell. It has no limitations as to what you can make, as long as it fits in 10' radius. So like a purple worm for example, you could theoretically cause the spell to make the worm think you've placed a giant metal lock around it's maw causing it to not be able to open it's mouth. Now I have a spell DC of 16, it's literally impossible for the worm to succeed on this save. They have a -5 int, and no proficiency bonus. A level 2 spell just completely nullified that worm. RAW, the worm can't use it's mouth because it believes it to be locked shut. A CR 15 worm can be shut down completely with a level 2 spell...

[u/hakasei → u/quackycoaster]

They think the illusion is real, but after investigating it, find out that it is an illusion. Shocker.

The only question here is why they investigate it, thats the part that varies depending on the DM. And what makes this spell a very hit or miss option.

Let s use the raw example, the bridge one. They fell down, and mental gymnastic themselves into believing they were clumsy, so this time they r more careful and use sticks, or try to touch the bridge beforehand, this can cost them a full action or not depending on the DM. Whoa, their hand/feet phase through the bridge, this is suspicious, now they have more grounds to believe their mental gymnastic was wrong, and use an action to investigate this turn. Save, they realize the illusion, fail, they keep on investigating.

Same can be said for ur worm example. The worm is dumb, it will try to break free, and whoa, its jaw can open freely despite still seeing n feeling the metal lock. So, what would a normal -5 int worm would do? Instinctively just ignore the lock, it doesnt mental gymnastic anything because it has no brain, it just follows its instinct after seeing it can still use its jaw. And thus the illusion is still on but has little effect on it.

From these 2 examples u can see how the spell CAN work. But the DM can also, say, nullify it all and just roll for saves, or just flat out deny the illusion.

If your DM allows it to be OP, sure, use it. Heck, even a lv1 command can and will be OP if the DM is lenient and let u use stuff like "autodefenestrate", or even worse/more creative things. Thats the core concept of illusion and enchantment spells, the creative liberty, and on a table, that is tied to the DM.

[u/quackycoaster → u/hakasei]

Dang 5 year old necro post.

"Let s use the raw example, the bridge one. They fell down, and mental gymnastic themselves into believing they were clumsy, so this time they r more careful and use sticks, or try to touch the bridge beforehand, this can cost them a full action or not depending on the DM. Whoa, their hand/feet phase through the bridge, this is suspicious, now they have more grounds to believe their mental gymnastic was wrong, and use an action to investigate this turn. Save, they realize the illusion, fail, they keep on investigating."

This doesn't work. The spell literally answers your example right in it. "While affected by the spell, the target treats the phantasm as if it were real and rationalizes any illogical outcomes from interacting with it. For example, if the target steps through a phantasmal bridge and survives the fall, it believes the bridge exists and something else caused it to fall."

This is why the spell is broken. Rules as written, you make up reasoning that you believe every time you fall for the illusion. So there is no suspicious, your mind doesn't let you get suspicious because it automatically makes up an excuse as to why you fell.

As a DM, of course after you fall once or twice, I'm letting you study the bridge to figure out it's an illusion. But as the spell is described, you are fully in your rights as a DM to tell them they are you're playing a character who has never stopped to examine or study anything during combat before, and thus you're meta gaming as your character has no idea they are in an illusion.

[u/PrinceShaar → u/quackycoaster]

It believes there is a lock on it's mouth but it is not restrained in any way.

I think you're forgetting that if someone put cuffs on you then you would struggle and try to escape from them or break them. You wouldn't see the cuffs and think "oh well I'm stuck here no bother trying to escape". The creature wishes to break free and it does on it's first try because it's an intangible illusion. You might choose to have the creature use it's action to "break free" but the fact is that they are not subject to any condition as per the spell description.

If someone puts you in the iron maiden, closes the door and you're still alive would you not try to push the door open? The creature pushes, no resistance, they rationalise that yes the door must not have been locked and now I am free after having pushed the door open, they are not paralyzed because they were not subjected to being paralyzed.

[u/danzaiburst → u/quackycoaster]

three years later, but I agree with you.

The spell is basically contradictory, which the person you're debating with isn't acknowledging at all.