Angkar, Apex of Savagery

Mutate {2}{r/g}{b}{b} (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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Menace, deathtouch
Whenever this creature mutates, each opponent sacrifices X creatures, where X is the number of times this creature has mutated.