Death's Lightning

You unleash a burst of dark, crackling lightning imbued with the essence of death. The lightning arcs in a 15-foot cone, searing those caught within it with unholy energy. The targets must succeed on a Dexterity saving throw or take 1d6 lightning damage plus 1d6 necrotic damage.

At Higher Levels. Both of the spell’s damage types increase by 1d6 when you reach 5th level (2d6 each), 11th level (3d6 each), and 17th level (4d6 each).