Ashnod, Deaths Caretaker

Ward—sacrifice a creature
Sacrifice a creature: add two mana in any combination of colors if this is the first time this abilities resolved this turn. If its the second,
draw a card. If its the third, create two 3/3 colorless zombie artifact creatures tokens. If its the fourth, return a nonland permanent with cmc less than or equal to the total cmc of creatures youve sacrificed to Ashnod, Deaths Caretaker.