Burning Darkness

Magical black fire spreads from a point you choose within range to fill a 30-foot-radius sphere until the spell ends. The darkness spreads around corners. A creature with darkvision can’t see through this darkness. Nonmagical light, as well as light created by spells of 4th level or lower, can’t illuminate the area.

The sounds of flames flickering can be heard within the sphere. Whenever a creature starts its turn in the sphere, it must make a Constitution saving throw, taking 4d8 fire damage on a failed save, or half as much damage on a successful one.