Concelhaut's Corrosive Siphon

The touch of your shadow-wreathed hand can siphon life force from others to heal your wounds. Make a melee spell attack against a creature within your reach. On a hit, the target takes 2d4 necrotic damage, and you regain hit points equal to half the amount of necrotic damage dealt. Until the spell ends, you can make the attack again on each of your turns as a bonus action.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d4 for each slot level above 4th.

This spell cannot be learned. It can only be cast using an interplanar artifact from Eora such as Concelhaut's Skull or Concelhaut's Ironclasped Grimoire.