Bloodthirst Dagger

Weapon (dagger), Uncommon
Blood sacrifice. You can spend a bonus action to dip this weapon in nearby wet blood, or spend an attack to harm yourself for exactly 1 damage (no rolls needed). When you dip it or take damage from the attack, the weapon is empowered: the next critical strike with this weapon within the next minute deals an additional 1d8 damage (included in the critical damage roll).