Blood Wilt

You draw the moisture from a creature within range. On a successful hit, a creature in that area must make a Constitution saving throw. Constructs, plants, and water elementals aren’t affected, and undead make this saving throw with disadvantage. A creature takes 2d6 necrotic damage on a failed save, or half as much damage on a successful one.

If you kill an enemy with this spell, you gain 1d6 hit points.