The DoomSlayer

+3: Put three +1/+1 counters on a creature you control and a +1/+1 counter on a creature an opponent controls.
-8: Destroy target Demon, Devil, Horror, Nightmare, Spirit, Sliver, or Eldrazi. You gain X life were X is its toughness.
-15: Exile all non-land permanats from play. Until your next turn, you may cast them, and spend mana as though it were mana of any color.