Bloodvial Purveyor is a rare Creature — Vampire card from Innistrad: Double Feature (DBL), collector number 365. Current market price: $0.66 (foil $1.42), TCGplayer market prices via Scryfall.
Flying, trample Whenever an opponent casts a spell, that player creates a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this token: Draw a card.") Whenever this creature attacks, it gets +1/+0 until end of turn for each Blood token defending player controls.