Oobli, Pet Project

Mutate {0}(If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Oobli, Pet Project can only mutate onto creatures that entered the battlefield from exile this turn.
{w}{u}{r}{g}: Exile all cards in this mutate pile, then return them to the battlefield mutated together in the reverse order.