Chain Spark

An orb of lightning flies toward a target of your choice within 60 feet of you. On a hit, the target takes 2d6 lightning damage. If another enemy is within 10 feet of a hit target, you may make another attack roll and have the electricity spread to them. It deals half damage to each target it hits. For each new target after that, the damage is halved from the previous half.

The spell adds 2d6 per level when cast at higher levels.