Holda, Avatar of Evolution

Mutate {5}{g}{u} (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.)
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Whenever Holda, Avatar of Evolution enters the battlefield or mutates, choose a creature.
Chosen creatures have all other abilities of Holda, Avatar of Evolution.