Nahiri's Sacrifice is a uncommon Sorcery card from Phyrexia: All Will Be One (ONE), collector number 142. Current market price: $0.18 (foil $0.20), TCGplayer market prices via Scryfall.
As an additional cost to cast this spell, sacrifice an artifact or creature with mana value X. Nahiri's Sacrifice deals X damage divided as you choose among any number of target creatures.