Geralf, Curiosity Stitcher

Each Zombie creature card in your hand and
in your graveyard has mutate. Its mutate cost is
equal to its casting cost.
(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
under it.).
{1}{b}{t} Until end of turn you may mutate a
zombie creature card from your graveyard onto another creature you control.