Polymorph Question :: Excess Damage (And resistances) [duplicate]

Question

Ok so if I polymorph a Fire Giant into a Baby Chicken and drop it into Lava the Baby Chicken will take 10d10 or 18d10 if I dunk it.

When it hits 0 it reverts back to its previous form and takes the excess damage, but what if the creature was immune.. like a fire giant? Does it assume to take all that damage because it was a Baby Chicken? Basically Im tryin to turn a giant into a nugget.

Answer 1

The fire giant is immune to the excess damage

If it reverts as a result of dropping to 0 hit points, any excess damage carries over to its normal form.

The excess damage still has a fire damage type. Fire giants are immune to fire damage, so he or she would not take any further damage from the lava.