Cthulhu, The Almighty

+10: All opponents are unable to harm Cthulhu or he/she who summoned him their next turn. Cthulhu is indestructible and hexproof forever.
+2: Opponents must sacrifice 5 creatures even if they have hexproof. Otherwise they take 1 damage for each card on the battlefield.
-20: All creatures gain +10/+10. If opponents attack before their next 5 turns they take the damage. It can't be avoided with hexproof or spells.