The year is 1980. The Empire Strikes Back is in theaters and Star Wars fever is running wild. Recently rising to popularity is a brand of underwear called Underoos which operate under a simple premise. License as many characters as you can and make underwear for kids based on those licenses.
Somewhere along the way someone at Underoos, perhaps a quiet loner people found unsettling, decided the best way to market this product was to show kids wearing it...and singing...and dancing. No one stopped him and what follows is one of the results.
success!