Circle of Decay

A sphere of negative energy ripples out in a 60-foot-radius sphere from a point within range. Each creature in that area must make a Constitution saving throw. A target takes 8d6 necrotic damage on a failed save, or half as much damage on a successful one. If a target dies, the body withers away, leaving a soul gem in its place. The strength of the soul gem varies depending on the strength of the creature. Refer to the Soul Gem table for more details.

At Higher Levels. When you cast this spell using a spell slot of 7th level or higher, the damage increases by 2d6 for each slot level above 6th.