Back in 1991, Nirvana appeared on the TV show Top of the Pops, a show generally reserved for pop musicians to lip sync their songs. Obviously, telling Nirvana to lip sync "Smells Like Teen Spirit" was a bad idea so the producers agreed to let Kurt sing live while the rest of the band would be on playback.
What resulted was one of the greatest trollings on television, with the band barely pretending to play their instruments while Cobain changed some of the lyrics and did his best Morrissey vocal impression.
Dave Grohl recalled the spectacle, saying that the show basically asked for it by not allowing them to play live and recalls some of the people in the audience trying to awkwardly dance to it.