Blood Blade

You transform the edge of one slashing weapon you touch, making it unnaturally sharp. Any creature struck by the weapon begins bleeding, suffering 3d6 damage at the beginning of each of its turn until the wound is stanched, either with magical healing or by spending an action and making a successful DC 10 Wisdom (Medicine) check. The Medicine check can be performed by the bleeding creature or by an adjacent ally. Creatures without blood are not affected by the blade. When the spell ends, the blade returns to its natural sharpness, but bleeding caused by the blade doesn’t end automatically.