Esenwein's Vampiric Blade

You power-up 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 then becomes drain the targets energy the target take 1d8 necrotic damage. half of the damage done in necrotic damage is added to your THP

This spell’s damage increases when you reach certain levels. At 5th level, the melee attack deals an extra 1d8 necrotic damage to the target on a hit, at 11th level (3d8) and again at 17th level (4d8).