So-Lo is the only solo album by Danny Elfman and was released in 1984. It was performed by members of his Californian band Oingo Boingo, but deliberately not released under the Oingo Boingo name in order to circumvent a dispute with the band's record label. Elfman stated that he used the opportunity to release material that would not be suitable for an actual Oingo Boingo album, moving away from the band's ska origins and more towards mainstream synthpop. He described it as "chance to experiment with slower tempos", with no intention of beginning a solo career.
Initial releases of the album featured a significantly different mix of the opening song Gratitude. The initial mix included alternate backing vocals and rhythm guitar, a different use of reverberation (mixed more dry) and a faded out ending with an additional guitar solo. The single release and accompanying music video used a revised mix of the song, which was subsequently issued on all re-releases of So-Lo on CD. (This is erroneously labelled the "short version"—the revised mix is actually four seconds longer than the original mix.) The most significant change from the original mix is the removal of a spoken verse (starting at 1:37) whose complete lyrics are: I used to eat people like you for breakfast; I used to fly, high up in the sky; I used to chew up rocks and spit out gravel; I had a heart as cold as ice. The original mix was only ever released digitally as part of the Beverly Hills Cop soundtrack compilation. However, the spoken verse was included in all live performances of the song, with slightly different lyrics.