In the mythology of Parliament, the Bop Gun was a weapon of sorts employed by Dr. Funkenstein. Sir Nose, who was "devoid of funk" could not dance until he was blasted by the Bop Gun, courtesy of Dr. Funkenstein and the Star Child. It was when he was hit by the Flashlight, the ammunition of the Bop Gun, that he was able to dance to the Aqua Boogie.

And yes, all of this was documented by Parliament songs.