Entropic Halo

A wave of dark, life-draining energy erupts from you in a 20-foot radius. Each creature in that area must make a Constitution saving throw. Each creature in the area of effect takes 8d6 necrotic damage on a failed save, or half as much damage on a successful one.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each slot level above 3rd.