Exsanguinating Blade

This double-bladed dagger has an ivory hilt, and its gold pommel is shaped into a woman's head with ruby eyes and a fanged mouth opened in a scream. You gain a +1 bonus to attack and damage rolls made with this magic weapon. When you roll a 20 on an attack roll made with this weapon against a creature that has blood, the dagger gains 1 charge. The dagger can hold 1 charge at a time. You can use a bonus action to expend 1 charge from the dagger to cause one of the following effects: - You or a creature you touch with the blade regains 2d8 hit points. - The next time you hit a creature that has blood with this weapon, it deals an extra 2d8 necrotic damage.