Shock Treatment was a sequel to Rocky Horror Picture Show.
Written by the same guy. Wasn’t near as good though.

lol dont think theirs anything like rocky horror. that film is a once in a lifetime experience.

But if your looking for oddball musicals, you can try

Across the Universe
Repo the Genetic Opera
Sweeney Todd
Dr. Horribles singalong blog

I listed some musicals that stray from the usual path:
Cabaret
Godspell
The Incredibly Strange Creatures Who Stopped Living and Became Mixed-Up Zombies!!?
Jesus Christ Superstar
Phantom of the Paradise
Repo! The Genetic Opera (2008)
Shock Treatment~sequel to “Rocky”
Tommy

“Zombies” is considered to be an inspiration for “Rocky”, as is “POTP”, whose outrageous character, Beef, reminds most fans of Dr. Frank N. Furter.

NOTE: There is a short also titled “Repo! The Genetic Opera”.