Worst 'SNL' Music Performances Ever (via @PopCrush)

To give you some proper perspective:
https://tvtropes.org/pmwiki/pmwiki.php/CreatorKiller/Music

In 1981, former cast member John Belushi convinced new Show Runner Dick Ebersol to book the Los Angeles punk band Fear, whose frontman Lee Ving was a friend of his, for the season 7 episode hosted by Donald Pleasence (on October 31, appropriately enough). What followed was a rowdy punk show complete with mosh pit that ended in a riot; among other things, Ebersol was hit in the chest with a pumpkin, somebody got on stage and shouted "fuck New York!" into the microphone, the crowd of actual punks bused in for the show (which included a young Ian MacKaye, Tesco Vee of the Meatmen, and multiple members of the Cro-Mags) trashed the SNL set, and NBC cut the broadcast short and went to commercial. Not only was Fear permanently banned from SNL, but they also found it much harder to tour afterward as venue owners who had seen the nationally-televised SNL performance refused to let them use their venues, greatly limiting their career prospects. (Not like the tried-and-true punks of Fear really cared about mainstream success, mind.)

Ashlee Simpson was expected to be the next Avril Lavigne, following in the footsteps of her big sister Jessica to become a major pop star. Her first album, Autobiography, went triple platinum, and like her sister, she had a successful Reality Show on MTV. Then came her disastrous performance on Saturday Night Live in October 2004, where she was caught lip-syncing when her band started playing the wrong song, followed by an embarrassing "hoe-down" when she realized what was happening. Following an equally disastrous half-time performance at the Orange Bowl a few months later, Ashlee's music career was all but over. Her following album, 2005's I Am Me, sold far less than Autobiography and didn't even reach the platinum mark, and her 2008 follow-up Bittersweet World was an out-and-out flop.