Major Organ and the Adding Machine is an Elephant 6 supergroup led by the elusive and possibly fictional Major Organ. The liner notes of the band's debut album, Major Organ and the Adding Machine, leave it a mystery as to who is officially featured. When performing live on the Holiday Surprise Tour, the members of the band wore paper masks to maintain their anonymity. It is believed that the main contributors are Jeff Mangum, Julian Koster, Robert Schneider, and Kevin Barnes, whose vocals are most obviously present on the album, but a number of other Elephant 6 musicians are believed to have contributed too, including members of The Olivia Tremor Control, Elf Power, and Of Montreal.
In 1997, when thought to be a side-project of Jeff Mangum and Julian Koster, Major Organ and the Adding Machine contributed a cover of Louis Armstrong's What a Wonderful World to a Kindercore Records Christmas compilation. Over the next few years, they recorded a self-titled album and released it on Orange Twin Records in 2001.