Arcing Lightning

Make a ranged spell attack against a creature within range. On a successful hit, the target takes 1d6 lightning damage. The lightning then arcs to another creature of your choice within 10 ft. of the original target who also takes 1d6 lightning damage.

This spell's damage increases by 1d6 when you reach 5th level (2d6), 11th level (3d6), and 17th level (4d6).