Polymorph/Sizing Question

[Scorponok]

Hey Giants, I have a question regarding the polymorph ability and how far it can actually go.

I have a player who is a Druid, and through various rules, has decided he would like to kill a dragon by polymorphing into a flea and going up the dragon's nostrils or eardrum, then polymorphing into something huge, thereby exploding the head of the dragon. From what another player tells me, they would both take crushing damage, but the Druid is the type of player who would not mind killing his own character if it results in something cool like that.

I am wondering how easy that is to do under RAW. During a battle, the dragon would be moving around and breathing all sorts of fury onto the party. But how easy would it be for the player to get close enough as a very tiny animal, aim themselves into the orifice of this dragon, and do this? Would it be a tumble check, dex check, etc.? If the dragon spots the flea (assuming a very high spot check) would it just chew the flea and the character just dies?

I wouldn't mind it terribly if the player does this, but I'm thinking the player is making it sound like it should be a cakewalk, and I'm thinking it should be harder than he's saying it would be.

[Troacctid]

It's impossible by RAW. There are no rules allowing you to do it and no rules to cover what would happen if you did.

[sideswipe]

i believe there actually is a rule that sort of covers this.... i have no idea where it is.

its along the lines of, if a creature uses swallow whole on you and you go to change your size you cannot become bigger then your confines.

example, a creature has swallow whole and can fit 8 medium creatures, or 2 large in its gullet. you can only increase from medium to large (or smaller).

its a shame i cannot find the quote. then again i may be making this up....

[Doc_Maynot]

Wouldn't this be under the same rules the Arseplomancer uses?

[Bronk]

It's impossible by RAW. There are no rules allowing you to do it and no rules to cover what would happen if you did.

The rules that would prevent this kind of burst damage are from the spell failure section:


SPELL FAILURE
If you ever try to cast a spell in conditions where the characteristics of the spell cannot be made to conform, the casting fails and the spell is wasted.