Void of bargain

For the duration, magical Darkness spreads from a point within range and fills a 15-foot-radius Sphere. Darkvision can’t see through it, and nonmagical light can’t illuminate it.

You shroud yourself in an aura of absolute darkness, emanating an oppressive void that saps the warmth and light from the area around you. For the duration, Dim Light within 10 feet of you becomes darkness, and Bright Light becomes Dim Light.

Everything and everyone in the range of 10 feet makes a constitution saving throw on a failed save gets hit for 4d6, on a save success you roll the damage but deal only half of it.