Polymorph spell clarification

[MarkVIIIMarc]

So lets say I cast Polymorph on a bad guy who fails the save. I turn him into a worm and put the worm into a small cage. Then I allow the bad guy to turn back to his humanoid form.

What happens? Does the cage break?

If I put the fellow into too tight a spot to become humanoid shape again what happens?

It seems like there is an exploit here pending DM decision.

[Potato_Priest]

What are you looking for here?

What happens in the rules as they are written?

What happens in the rules as intended?

A reasonable houserule?

Clarifying that will really help us have a productive discussion that will help you out.

[MarkVIIIMarc]

Oh sorry. What a can of worms I have opened.

Now I'm curious the differences.

How about rules as intended AND what I can expect most DMs to do.

[Legendairy]

As a dm I would say the cage would break and cause a bit of damage, you put them in a small crack and drop it they would die. Most things of higher levels can deal with the spell and things that can’t usually aren’t the movers and shakers behind the scenes. So, have fun with it. Now a lot I’ve seen rule it to shunt then to the closest unoccupied space. So it’s either way. Just letting you know how I would handle it personally. There is a plethora of people more apt at answering RAW and RAI.

[dejarnjc]

So lets say I cast Polymorph on a bad guy who fails the save. I turn him into a worm and put the worm into a small cage. Then I allow the bad guy to turn back to his humanoid form.

What happens? Does the cage break?

If I put the fellow into too tight a spot to become humanoid shape again what happens?

It seems like there is an exploit here pending DM decision.

With all these sorts of questions that involve the polymorph spell my own personal ruling is that if the space a polymorphed target is in is already occupied then they are shunted to the nearest unoccupied space. I also apply this rule to wildshaped druids who voluntarily let themselves be swallowed.

[mer.c]

With all these sorts of questions that involve the polymorph spell my own personal ruling is that if the space a polymorphed target is in is already occupied then they are shunted to the nearest unoccupied space. I also apply this rule to wildshaped druids who voluntarily let themselves be swallowed.

A nice thing about this ruling is that it’s consistent with a lot of other 5e rules involving similar things (like Meld With Stone ending while you’re melded). Usually there’s some damage involved as well.

[Blacky the Blackball]

My group have decided that the general house rule for this sort of situation is that the foe would remain trapped in worm form until released from the cage.

That seems to fit the fictional trope best, and when applied evenly across the board (i.e. any time a change of shape isn't possible due to lack of space it fails to happen - and this may result in a spell or ability lasting longer than it should until it's possible for it to end) it's proven to be pretty fair.