See You Later, Alligator

The Six O'Clock News on BBC Radio 4 reported that Bobby Charles had died. In 1955 he wrote the song See You Later, Alligator, which was a big hit for Bill Haley and the Comets. Apparently, he was leaving a cafe one evening and shouted the phrase to a friend. A drunken passer-by shouted back "After a while, crocodile". The rest is history ...

The phrase 'see you later, alligator' is in the OED. Alligator here was a slang word in use in the US at the time and meant a devotee of swing music.