Ethereal Storm

You create a tempest of ethereal energy that sweeps through all enemies within a 40-foot square, dealing 6d8 necrotic damage. Each affected creature must make a Constitution saving throw. On a failed save, the creature takes full necrotic damage; on a successful save, the creature takes half damage.

The damage dealt by Ethereal Strom increases by 1d8 for each spell level above 4th.