The Buffy the Vampire Slayer theme tune was written and performed by the band Nerf Herder. The band took their name from a line in The Empire Strikes Back where Princess Leia called Han Solo a “stuck-up, half-witted, scruffy looking nerf herder”. Joss Whedon said in his DVD commentary for Welcome to the Hellmouth that Alyson Hannigan brought the band to his attention by constantly playing their self-titled first album. Joss contacted them to compose Buffy’s title music.
Nerf Herder’s original recording of the Buffy theme tune had a point where the beat was lost slightly and it had to be re-recorded. The theme tune is available on the compilation Buffy the Vampire Slayer: The Album (1999, TVT Records). Nerf Herder’s song ‘Vivian’ (from How to Meet Girls, 2000) played during the episode Who Are You? when Faith (in Buffy’s body) danced at the Bronze.
The band appeared onstage in Empty Places when Faith, the Potentials and Dawn went dancing there, playing ‘Rock City News’ and ‘Mr. Spock’. Kennedy said in that episode, “What kind of band plays during an apocalypse?” to which Dawn replied, “I think this band might actually be one of the signs”.