Dark Soul

A mass of shadowy gloom pursues a point you choose within range and engulfs the area in calming dark. Each creature in a 15-foot-radius sphere centered on that point must make a Constitution saving throw. A creature takes 6d8 necrotic damage on a failed save, or half as much damage on a successful one. A creature that fails its save by 5 or more also suffers 1 point of exhaustion. 

The darkness spreads around corners then immediately dissipates. It rots organic matter like flesh and plants on contact.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d8 for each slot level above 3rd.