Ok take this. I was trying to learn vJASS to make it and more of course.
It like chain lightning but different in hitting the target. You cast the lightning bolt at a target it takes initial constant damage like 10 not between min-max damage. If there are no enemies around the target then only the initial damage is dealt but if there are N# of enemy around the target, lets say 5. The lightning bolt will split to hit each target with damage range, lets say 10-25. When every target is damaged their total amount of damage is reflected back to the original target.
EX:
Primary Target takes 10 damage
Secondary Target 1 takes 10
Secondary Target 2 takes 15
Secondary Target 3 takes 20
Secondary Target 4 takes 13
Secondary Target 5 takes 23
Total damage 81
That damage will reflect back to the Primary target in adition to the Initial damage (10), so the total damage of the primary target will 91.