Ob Nixilis, the Destroyer

At the beginning of your upkeep, choose one;
*Place a +1/+1 counter on Ob nixilis, Destroy target creature you control and one that you don’t
*Place a -3/-3 counter on Ob Nixilis, Create a 6/6 Demon token with Flying, activate this only if Ob Nixilis has Toughness of 3 or more
*Place a -7/-7 counter on Ob Nixilis, Sacrifice all your creatures, deal damage to all opponents equal to their total converted mana cost
Ob Nixilis does not heal to full toughness at the end of your turn