"Monster Mash" has weird background vocals about tennis shoes and nobody knows why

The lyrics of Bobby "Boris" Pickett's classic 1962 Halloween jam "Monster Mash" mostly make sense, with one weird exception: The background vocalists sing about a tennis shoe. Why? Nobody knows and even Pickett himself couldn't remember during a Dr. Demento interview in 2006, the year before he died.

"[They're saying] 'Ooh, tennis shoe, wah-ooh," he told Dr. Demento. "We don't know why."

From The Hill:

[The song] was written by Pickett and Lenny Capizzi, his bandmate in a group called The Cordials. The idea came about after Pickett began demonstrating his Boris Karloff impressions during the band's cover of "Little Darlin'," a 1957 song made famous by The Diamonds. Specifically, Pickett would perform the song's monologue ("My darlin', I need you…") in his Karloff voice, much to the audience's amusement.

(Thanks, Bob Pescovitz!)