The Ren & Stimpy Show (non-existent unused Kurt Cobain song for Nickelodeon animated series; 1990)
In 1990, before Kurt Cobain hit it big with his band, Nirvana, he was a struggling, starving musician. It is rumored that one of his many stabs at fame was penning a theme song for the famous cartoon, Ren and Stimpy.
The story goes that Cobain recorded the song on the cheap, but felt proud of it. Studio executives at Nickelodeon heard the song, thought it was awful, and then threw it out. But after Nirvana had become famous with their 1991 album, Nevermind, the executives realized this decision was a mistake.
No copies of the alleged song have been released, and as such the songs existence has not been confirmed. Even if copies of the song still exist (assuming it even did in the first place), It is said that the version Nickelodeon had were trashed, making it unlikely that any of the executives hold a copy. Cobain's estate has not commented on the matter.