Thanos

+3: Spawn 4 black 2/1 Outrider creature tokens with haste and trample.
-8: Add 10 mana of any color to your mana pool. Any Black Order creature in your hand may be played without having to pay its mana cost.
-20: Destroy all of target opponent's creatures. Their planewalkers' loyalties are reduced to 1 and half of their other permanents are destroyed.