Chain Lightning

You shoot out a lightning bolt that splits off, targeting new targets after it hits the first one. Each additional target reduces the damage dice by one until no more dice remain. The first target takes 5d8 damage, the second takes 4d8, the third takes 3d8, the fourth takes 2d8, and the fifth takes 1d8. You can chain the indicated damage.

Each target of the spell must make a reaction check to avoid the bolt. If a target passes their check, the lightning continues to travel in the direction past the missed target to another target within 20ft. of the missed target. The damage does not decrease unless a target is hit. You do not control who the lightning strikes after the initial target.

The closest target from the previously hit target is the next target (excluding the previously hit target). Otherwise, for targets that are equal distance from the source, roll a die that is closest to how many targets there are. If two targets, roll 1d4 (1-2 is one, 3-4 is two), three targets roll, 1d6 (1-2 is one, 3-4 is two, 5-6 is three). For an odd number of targets, roll the next die up and any extra numbers are re-rolled (i.e. if five targets, roll 1d6 and re-roll sixes).