Many songs by The Beatles include weird outtakes that make their way into the final recording. From a curse word in “Hey Jude” to Ringo Starr’s “blisters on me fingers” exclamation at the end of “Helter Skelter”, it’s amazing how many memorable moments in Beatles’ history happened by accident. One bizarre moment at the end of a Beatles song features Paul McCartney acting like a dog, but it does fit the theme considering the title.
“Hey Bulldog” was released in 1969 on the Yellow Submarine soundtrack. John Lennon wrote the song, but the recording of it was improvisational and free-spirited. The end of the track features a skit where Lennon is talking to a dog, played by McCartney. The dog howls and barks in response to Lennon while the two cackle like hyenas.
In an interview, McCartney said it wasn’t planned, and he just started barking in response to Lennon. It’s a segment he likes because it captures the “spirit of that session.”
Source: Ross Tanenbaum/cheatsheet.com