The tune was improvised by Pete Townshend, John Entwistle, Keith Moon and keyboardist Nicky Hopkins.
A jingle based on this tune was released as "Top Gear" on both reissues of The Who Sell Out (1967).
[4] The title is a nickname given to Entwistle by the band, because of his strong constitution and seeming ability to "Eat, drink or do more than the rest of them."
The only known live appearance of this song was in a medley of "My Generation" at the Concertgebouw in Amsterdam, Netherlands on 29 September 1969, part of the Tommy tour.
Rolling Stone's John Swenson described "The Ox" and "My Generation" to be "sonic marvels of the time" due to Townshend's feedback technique on these songs.