Ball Lightning

A bright streak flashes from your pointing finger to a point you choose within range and then blossoms with a low roar into an explosion of flame. Each creature in a 20-foot-radius sphere centered on that point must make a Constitution saving throw. A target takes 6d8 lightning damage on a failed save, or half as much damage on a successful one.

The lightning arcs towards creatures wearing metal armor or holding metal objects within a 30-foot-radius of the origin dealing an additional 1d6 lightning damage.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage of the arcing lightning increases by 1d8 for each slot level above 3rd.