Can't believe I forgot this one, but: Root Boy Slim and The Sex Change Band", active mainly the late 70s. Apart from some fringe notoriety for "Boogie 'til you Puke" (the very first song on their very first album), they never hit it big, but they played blues with a comedic twist. One of the best live acts I ever saw depending on what drugs Root, a notorious stoner, had in his system during the show. The following quote from rootboyslim.com, started by a former band member, sums it up:
Writing a biography of an artist is usually a straightforward process. You list the date of birth, throw in some astrological crap, talk about all the gold and platinum records the artist has received, maybe even toss in a few quotes of a philosophical nature to show what a deep thinker the artist is. Unfortunately, that approach just won't work with Root Boy Slim.
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Also Dread Zeppelin, a band specializing in reggae Led Zep renditions whose lead singer is.. wait for it... an Elvis impersonator. But only the original singer, Bill "Tortelvis" Tortell; the one they had later sucked.