Forced Adaptation

As an additional cost to cast this spell, reveal a
non-Human creature card from your hand with
converted mana cost equal to X.
The revealed creature card gains mutate until
end of turn. You may cast it as a mutating
creature spell without paying its mana 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.).