Carc, Keeper of Lore

+1: (You may cast this ability as if it was an instant)Carc becomes a 1/5 legendary Crab creature with defender until end of turn.
0: Select one creature, they are now a crab in addition to their other types.
-3: Choose a creature card in your hand, they are now a crab, and have Mutate, with their mutate cost being their normal mana cost .