Massacre Wurm is a mythic Creature — Phyrexian Wurm card from Murders at Karlov Manor Commander (MKC), collector number 130. Current market price: $4.83, 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.