This attack's effectiveness is actually influenced on how fast you're currently traveling, and the attack cannot change direction. Basically, you're running straight at your target and punching them before you even get close, to fire off a blast of light that has a tail that is quite like a comet, hence, the name.
Start by making a fist with your left hand.
Charge White Light into the fist so that it is glowing with energy.
Either punch and release the energy or start running and release.
Result is a comet-like blast of energy that will be faster and stronger if you were running.
Repeat all steps list aove, but make it with Blue Light.
The result is two comets that spin around each other as they fly towards the target.
Repeat all steps list aove, but make it with Prism Light.
The result is three comets that spin around each other as they fly towards the target.
Repeat all steps list aove, but make it with Gold Light.
The result is four comets, with a single giant one in the center, with the other three that spin around the center one as they fly towards the target.
If time were an item then people would think before they used it.