Cloudpiercer
From Ikoria: Lair of Behemoths set
Cloudpiercer
Creature — Dinosaur
5/4
Mutate (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.)
Reach
Whenever this creature mutates, you may discard a card. If you do, draw a card.