Thraximundar is a mythic Legendary Creature — Zombie Assassin card from Commander 2013 (C13), collector number 221. Current market price: $0.83, TCGplayer market prices via Scryfall.
Haste Whenever Thraximundar attacks, defending player sacrifices a creature of their choice. Whenever a player sacrifices a creature, you may put a +1/+1 counter on Thraximundar.