D&D 5E Phantasmal Force's non-saving throw--how would you handle?

[kerbarian]

Could a caster cause the victim to imagine that bladed chains suddenly erupted from the ground and completely engulfed them? Thus allowing for damage and restraining, if not paralyzing, the target? What would you think of an automatic investigation check to escape every round with that or would they still need to stop struggling and specifically investigate the chains?

Yes, this is the main way I've seen Phantasmal Force used. Make the target believe they're in a situation where they can't see, can't attack, and can't escape. e.g. inside a box made of cloudy ice as if someone had cast Wall of Ice. If you believe the illusion, you'll likely try to attack the walls and break your way out rather than sit there suffering cold damage and contemplating whether the walls are real. In the meantime, you're not moving or attacking the caster and their allies (you believe you can't) and the caster and their allies can attack you with advantage (you can't see them).

If targets behave in a realistic manner, Phantasmal Force can usually have the effect of a 4th- or 5th-level spell (similar to Banishment or Hold Monster) plus a little bit of damage.

One loophole is that you need to convince the target not to try to move. If the target believes they're wrapped in bladed chains but an ally tells them "Walk towards me and you'll be free!" and they try it, they'll be able to and the chains will fall away as soon as they leave the affected 10' cube. They'll still believe the chains are real but will rationalize that they (for whatever reason) move with you or release you when you try to walk.

Getting around Phantasmal Force by convincing the targets to move (and bringing it back down closer to an appropriate power level) requires what I consider some pretty implausible metagaming, though, especially for low-intelligence creatures. Also, you can set it up so that a target who moves away will have to suffer attacks of opportunity to do so.

 

[Krachek]

I just find out that Golem are not immune to phantasmal force.
They are immune to Charmed and Frightened effects, but this spell pass in the crack!
With their 3 int, good luck to save, and forget any attempt to make an investigation check.

 

[77IM]

Golems are immune. The last sentence of the first paragraph of phantasmal force: "This spell has no effect on undead or constructs."

 

[Krachek]

Thank

 

[UngeheuerLich]

A very powerful spell depending on the reading. The 10 ft cube is also questionable as it may or may not move with the target. I am also not sure if the phantasm can be set to react to the targets movement in a realistical manner. I.e. would you walk out of the chains or will they move with you.
Also the target could be paralyzed by the chains. What happens if the target is attacked with a real sword... difficult to imagine how the sword may hot you through the chains. Would the blade cut the chains and you get out? Or could the caster süecify what will happen in such a situation as he is still concentrating on the spell. Maybe arcana vs investigation contest?

 

[Stormdale]

Phantasmal force is my favourite 2nd level spell. We’ve ruled that you can use your action to interact with the phantasm and get an investigation check (loss of attack being a big enough loss) to try to end the effect (after a few mock battles where I had our fighter types gnashing their teeth in frustration not being able to act for 10 rounds and taking 1d6 per round after failing their Int save).

IMO the key to using it is to focus on effects that immobilise your opponent- a 10ft block of stone falling from the ceiling and pinning/crushing the creature beneath it- added bonus target is prone beneath the stone and so easier for your allies to hit. The above mentioned encase them in a 10ft block of ice ala a wall of ice spell works too- both of these give reason to do 1d6 damage. Other options are an iron 10 ft cube prison cell bars could stop an opponent chasing you but is hard to justify a damage effect.

I see illusionary archers firing a 1d6 auto hit arrow, or other creatures attacking, a bit of a waste but could have distraction value under the right circumstances.

My group never rated it as a spell till I started using it (was trying to recreate a 1e gnomish illusionist and phantasmal force was always one of my go to spells) and it has changed many a battle in our favour.

Stormdale

 

[PnPgamer]

Phantasmal force is my favourite 2nd level spell. We’ve ruled that you can use your action to interact with the phantasm and get an investigation check (loss of attack being a big enough loss) to try to end the effect (after a few mock battles where I had our fighter types gnashing their teeth in frustration not being able to act for 10 rounds and taking 1d6 per round after failing their Int save).

IMO the key to using it is to focus on effects that immobilise your opponent- a 10ft block of stone falling from the ceiling and pinning/crushing the creature beneath it- added bonus target is prone beneath the stone and so easier for your allies to hit. The above mentioned encase them in a 10ft block of ice ala a wall of ice spell works too- both of these give reason to do 1d6 damage. Other options are an iron 10 ft cube prison cell bars could stop an opponent chasing you but is hard to justify a damage effect.

I see illusionary archers firing a 1d6 auto hit arrow, or other creatures attacking, a bit of a waste but could have distraction value under the right circumstances.

My group never rated it as a spell till I started using it (was trying to recreate a 1e gnomish illusionist and phantasmal force was always one of my go to spells) and it has changed many a battle in our favour.

Stormdale

Really nice uses. I got to say that our group has dismissed it as a really bad one, so nobody uses it.