Cauldon of the Dying World

Whenever Cauldon of the Dying World deals combat damage to a player, you may sacrifice a creature. If you do, put a number of +1/+1 counters on Cauldon equal to that creature's power.
If Cauldon of the Dying World would die, instead he deals damage to each player equal to its power. Then exile him and return him to the battlefield transformed under his owner's control.