Death's Grasp

One creature of your choice within range must make a Constitution saving throw. The target takes 2d8 Necrotic damage on a failed save or half as much damage on a successful one.

Before the target makes its saving throw, you can empower the spell by rolling one or two d8s. You lose Hit Points equal to the total rolled, and the spell’s damage increases by the same amount. This Hit Point loss can't be reduced or prevented.

Using a Higher-Level Spell Slot. The spell’s initial damage increases by 1d8 for each spell slot level above 1.