"Hey Bulldog" is a song by The Beatles which first appeared on the Yellow Submarine soundtrack album in 1968. Written by John Lennon (credited to Lennon/McCartney), the song was recorded during the filming of the "Lady Madonna" promotional video, and is one of the few Beatles songs to revolve around a piano riff.
During the recording, Paul McCartney started to bark without warning. The next lines, initially written as…
Sheepdog, standing in the rain
Bullfrog, doing it again
Some kind of happiness is
Measured out in miles