Zaxtar, Lord of Vengeance

Flying, trample
Whenever a creature an opponent controls attacks, put a vengeance counter on this creature.
Remove three vengeance counter from this creature: target opponent discards a card, sacrifices a creature, and loses 3 life.
Remove five vengeance counters from this creature: target opponent discards five cards.
Remove ten vengeance counters from this creature: destroy any number of target creatures.