Arc

You unleash a burst of electricity at a creature within range. Make a ranged spell attack against the target. On a hit, the target takes 2d4 lightning damage. If you roll the same number on both d4s, the lightning arcs from the target to a different creature of your choice within 30 feet of it. Make a new attack roll against the new target, and make a new damage roll, which could cause the lightning to chain again. At higher levels, select only two die to be capable of chaining before you roll damage.

This spell's damage increases by 2d4 when you reach 5th level (4d4), 11th level (6d4), and 17th level (8d4).