Sinuous Striker

{U}: This creature gets +1/-1 until end of turn. Eternalize—{3}{U}{U}, Discard a card. ({3}{U}{U}, Discard a card, Exile this card from your graveyard: Create a token that's a copy of it, except it's a 4/4 black Zombie Snake Warrior with no mana cost. Eternalize only as a sorcery.)