Circle of Death

6th-level necromancy
Casting Time: 1 action
Components: VSM the powder of a crushed black pearl worth at least 500 gp
Range: 150 feet
Duration: Instantaneous
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.
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.