Ghidorah, King of the Cosmos

Mutate [3][R/G][U][U] (If you cast this spell for its mutate cost, put it over/under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)

Flying, trample

Whenever this creature mutates, exile cards from the top of your library until you exile a nonland permanent card. Put that card onto the battlefield/into your hand.