Spirit Bomb+Big Bang+Kamehameha
1.Lift your least dominant hand over your head, and make a spirit bomb in it, while in the other hand make a big bang.
2.Bring the attacks together into a cupped shape in both hands (in the Kamehameha stance) and make a Kamehameha.
3.Thrust your hands forwards and make sure you aim good.
It can disintegrate the most that any attack can, and I don't know about anyone else, but I do know a way to make it to where it could destroy a small town.