Covenant of Blood is a common Sorcery card from Magic 2015 (M15), collector number 91. Current market price: $0.07 (foil $0.25), TCGplayer market prices via Scryfall.
Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.) Covenant of Blood deals 4 damage to any target and you gain 4 life.