Prey Snatcher

Mutate {3}{g}{g} (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.)
Whenever this creature mutates, it deals damage
equal to its power to target creature. If that
creature dies this turn, Prey Snatcher becomes a
copy of that creature.