Arc Lighting

A crackling bolt of lightning streaks from you toward a creature within range. The target must make a Dexterity saving through. On a failed save, the electrical energy arcs to 2 additional creatures within 10 ft of the target and all affected creatures take 1d8 lightning damage. On a save, the target takes half damage and the lightning does not arc.

The spell's damage increases by 1d8 when you reach 5th level (2d8), 11th level (3d8), and 17th level (4d8).