LogFAQs > #968935445

he's not exiled, he goes AWOL

the mission was probably to conquer Earth

edit: or at least explore it, something like Forbidden Planet (mentioned in the opening song).

In any case, when Frank sees King Kong on Earth, he's so impressed with Fae Ray's dress that he abandons his mission, and everything is good for a while. Riff Raff and Magenta are his partners, and he later becomes infatuated with Eddie, and then Columbia, and then Columbia falls hard for Eddie, who Frank is now jealous of (and feels scorned by). So he uses Eddie's brain to make Rocky, deciding that he doesn't want to deal with people anymore, and he'll make the world in his image.

He recruits Janet, Brad, and the Professor into his cult. They'll be his new groupies for the foreseeable future.

Riff Raff sees him using the medusa beam and realizes Frank is unhinged; so takes over, kicks out the earthlings, and they all go back. we don't know what will happen.