Massacre Wurm is a mythic Creature — Phyrexian Wurm card from Duskmourn: House of Horror Commander (DSC), collector number 147. Current market price: $4.96, TCGplayer market prices via Scryfall.
When this creature enters, creatures your opponents control get -2/-2 until end of turn. Whenever a creature an opponent controls dies, that player loses 2 life.