Leviathan, Primal Lord

+5: choose one, give target dragon +5/+1 and trample this turn, or deal 5 damage to all non-dragon creatures
-10: deal X damage to your opponent and all creatures they control where X is the amount of damage dealt on your opponents last turn, draw 2 cards
-20: Leviathan becomes a 12/10 creature, summon a 0/7 egg with "Deal 1 damage to this at the start of your turn, when this dies, summon Leviathan"