Drain Essence

You extend your hand towards a creature of your choice that you can see, the creature then has to make a constitution saving throw against your spell save dc, if the creature is undead, it has disadvantage on this save. The creature takes 3d6 necrotic damage on a failed save, and half as much on a success. After rolling the damage for the attack, you heal by the same amount, the value is the same as the damage done, so on a successful save from the creature you chose, you take half of the value in healing.

When you cast this spell using a slot of 3rd level or higher, the damage and healing increases by 1d6 per slot level.