Dispairing Blade

You brandish the weapon used in the spell’s casting and make a melee attack with it against one creature within 5 feet of you. On a hit, the target suffers the weapon attack’s normal effects and is ravaged by antilife. If the target has all of its hit points, the target takes 1d6 necrotic damage.

This spell’s damage increases when you reach certain levels. At 5th level, the melee attack deals an extra 1d6 necrotic damage to the target on a hit, and the damage the target takes for having all its hit points increases to 2d6. Both damage rolls increase by 1d6 at 11th level (2d6 and 3d6) and again at 17th level (3d6 and 4d6).