Helvault is a mythic Legendary Artifact card from The List (PLST), collector number DKA-151. Current market price: $0.39, TCGplayer market prices via Scryfall.
{1}, {T}: Exile target creature you control. {7}, {T}: Exile target creature you don't control. When Helvault is put into a graveyard from the battlefield, return all cards exiled with it to the battlefield under their owners' control.