Marina Vendrell's Grimoire is a rare Legendary Artifact — Book card from Duskmourn: House of Horror (DSK), collector number 64. Current market price: $0.31 (foil $0.35), TCGplayer market prices via Scryfall.
When Marina Vendrell's Grimoire enters, if you cast it, draw five cards. You have no maximum hand size and don't lose the game for having 0 or less life. Whenever you gain life, draw that many cards. Whenever you lose life, discard that many cards. Then if you have no cards in hand, you lose the game.