Valgavoth, Terror Eater is a mythic Legendary Creature — Elder Demon card from Duskmourn: House of Horror Promos (PDSK), collector number 120p. Current market price: $18.26 (foil $18.59), TCGplayer market prices via Scryfall.
Flying, lifelink Ward—Sacrifice three nonland permanents. If a card you didn't control would be put into an opponent's graveyard from anywhere, exile it instead. During your turn, you may play cards exiled with Valgavoth. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.