According to the theory, McCartney died in a car crash and, to spare the public from grief, the surviving Beatles replaced him with the winner of a McCartney look-alike contest, sometimes identified as "William Campbell" or "Billy Shears". Afterwards, the band left messages in their music and album artwork to communicate the truth to their fans. These include the 1968 song "Glass Onion", in which Lennon sings "here's another clue for you all / the walrus was Paul", and the cover photo of their album Abbey Road, in which McCartney is shown barefoot and walking out of step with his bandmates.