"905" is a song written by bassist John Entwistle for British rock band The Who's eighth studio album, Who Are You. It makes heavy use of one of the first multiphonic Polymoog synthesizers at Entwistle's studio in Ealing. Like Entwistle's other contributions to the album, it was never performed live by the Who, but was often performed by The John Entwistle Band. However, it was released as the B-side of the second single from the album, headed by another Entwistle song, "Trick of the Light", making it the only single by the Who with both sides written by John Entwistle. "905" was written for a never completed rock opera set in the future.
I had started a concept album along the same lines as Lifehouse. My story was a little different. It was set in the future. I put it on the shelf for a long time. When that album came along I took them off the shelf and changed them around a little bit. But '905' was actually one of the songs from that. The hero's name was '905' and he lives with this guy named '503' and they're absolutely identical. There aren't any women around because that's what they're eating.
— John Entwistle
The lyrics describe a cloned human implanted with memories instead of having an actual childhood, and was created to serve an unspecified purpose and is unable to do anything else. He knows though that at least at the end of his life his soul will be free from his manufactured existence.