Otrimi, the Ever-Playful (Commander 2020) [Oversize Cards]

Mutate 1BGU (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.)

Trample

Whenever this creature deals combat damage to a player, return target creature card with mutate from your graveyard to your hand.