Ceremonial Knife is a common Artifact — Equipment card from Innistrad: Crimson Vow (VOW), collector number 254. Current market price: $0.16 (foil $0.29), TCGplayer market prices via Scryfall.
Equipped creature gets +1/+0 and has "Whenever this creature deals combat damage, create a Blood token." (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this token: Draw a card.") Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)