I read it elsewhere. Personal opinion, I would not have made the base dmg 100k.
I've would've made it something like 2 True (unmitigateable) Dmg and then have it apply a debuff of double dmg for 0.1 seconds on each hit. Then I would've made the debuff stackable and have said stacks be inifinite. So it would be a ramp up attack.
I would've also just allow all previous spells in Light Attribute gain the Ray Affect to a limit.