Arc

A bolt of lightning arcs out from your hand at a creature you can see within range. Make a ranged spell attack. On a hit, the target takes 4d6 lightning damage, and the bolt arcs to a new target within 30 feet of the original target. The new target takes 2d6 lightning damage. Both affected targets must also make a Constitution saving throw. On a fail, they are also stunned until the end of your next turn.

At higher levels, the amount of damage the first target takes increases by 1d6 for each spell slot level above 2nd. The amount of damage the second target takes increases to 3d6 at 4th level, 4d6 at 6th level, and 5d6 at 8th level.