Iyosh, Conqueror of Towers

Level up and mutate abilities you activate cost {1} for each time this creature has mutated.
Whenever this creature attacks, reveal cards from
the top of your library until you reveal a creature
card. That card gains mutate and flash until end
of turn. You may cast that card this turn. The
mutate cost is equal to the creature's mana value.
Put the other revealed cards on the bottom of
your library in a random order.