Swallowed whole and baleful polymorph

[Calthropstu]

So a t-rex swallows a wizard. And the wizard casts baleful polymorph (eschew materials, still spell) at the t-rex.

What happens?

[Geddy2112]

I would say the new form would prove fatal, as the thing is polymorphed it will die when it shrinks and the wizard bursts from it. It would get +4 to save against it as the new form is fatal, but otherwise dies in the transformation freeing whatever it swallowed.

[Ashtagon]

I's say the ex-rex regurgitates the wizard if the new form cannot contain the wizard in its stomach.

Aren't swallowed wizards considered grappled though? If so, doesn't that stop the spell being cast (unless metamagic of course)?

http://www.d20srd.org/srd/magicOverview/castingSpells.htm#spellFailure

The other option is that the spell simply fails if the new form cannot contain the wizard, as the creature cannot conform to the desired parameters. This is a similar interpretation to enlarge person (http://www.d20srd.org/srd/spells/enlargePerson.htm), which fails if the physical space available is not appropriate to the new size.

[Calthropstu]

I's say the ex-rex regurgitates the wizard if the new form cannot contain the wizard in its stomach.

Aren't swallowed wizards considered grappled though? If so, doesn't that stop the spell being cast (unless metamagic of course)?

http://www.d20srd.org/srd/magicOverview/castingSpells.htm#spellFailure

The other option is that the spell simply fails if the new form cannot contain the wizard, as the creature cannot conform to the desired parameters. This is a similar interpretation to enlarge person (http://www.d20srd.org/srd/spells/enlargePerson.htm), which fails if the physical space available is not appropriate to the new size.

I specified eschew materials and still spell.

And, while enlarge does denote this, few others do. Making this a fiat to apply.

I like the regurgitation idea better than "exploding trex)

But swallow whole and teleporting/planar binding/summoning/ polymorphing etc all lead to rules quandries where dm fiat is required.

Would be nice to get an faq done on swallow whole.

[Extra Anchovies]

Enlarge Person states that it causes growth, but Baleful Polymorph has nothing to say on whether the creature, in its transition from one form to the next, briefly takes on one or more forms that lie somewhere in between. The t-rex doesn't necessarily shrink and shift into a frog over the course of the spell's standard-action casting time; it's just as likely that at some point during that time it instantly assumes a new size and shape. If we assume the change in size and shape is instant rather than gradual, the t-rex standing on the ground would be replaced by a frog sitting on the ground and the wizard would go from occupying an area of space surrounded by dinosaur to occupying an area of space surrounded by more open space, and the wizard would subsequently fall to the ground. I was going to estimate exactly how high off the ground the wizard would be, but then I remembered that the Swallow Whole ability makes absolutely zero sense for creatures that are even pretending to follow real-world biological mechanisms. Probably best to just handwave any fall damage as being negated by the spell or something.