Xathrid Demon is a mythic Creature — Demon card from Magic 2010 (M10), collector number 122. Current market price: $0.63 (foil $3.80), TCGplayer market prices via Scryfall.
Flying, trample At the beginning of your upkeep, sacrifice a creature other than this creature, then each opponent loses life equal to the sacrificed creature's power. If you can't sacrifice a creature, tap this creature and you lose 7 life.