Dignified Unicorn

Mutate {2}{w}{w} (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 this creature mutates, put a +1/+1
counter on it. If its name is Dignified Unicorn, it
gets +1/+0 and gains first strike and lifelink until
end of turn.