Patron of the Kitsune is a rare Legendary Creature — Spirit card from Betrayers of Kamigawa (BOK), collector number 19. Current market price: $1.69 (foil $21.79), TCGplayer market prices via Scryfall.
Fox offering (You may cast this spell any time you could cast an instant by sacrificing a Fox and paying the difference in mana costs between this and the sacrificed Fox. Mana cost includes color.) Whenever a creature attacks, you may gain 1 life.