Listen to this song. It's a well known classic by the Fendermen known as Mule Skinner Blues. The style is called Rockabilly, which is a fusion of Hillybilly and Rock and Roll from the mid 1950s.

John K always used mid 20th century stuff as inspiration in his work; from the coloring to the artwork and even the music and furniture in the cartoons.

Now tell me this song wasn't used as inspiration at least a couple of times in different episodes. Even the name of the song...