Black Flare

A blast of crackling black fire erupts from your hand, charring your target's flesh and burning their souls.. The target must make a Dexterity saving throw. A creature takes 6d6 fire damage and 6d6 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 6th level or higher,  the fire damage or the necrotic damage (your choice) increases by 1d6 for each slot level above 5th.