The rock band R.E.M. appears as guest stars in the episode. Mike Scully said that R.E.M. were "big fans of the show" and that their appearance was a "fairly last-minute addition". R.E.M. did not want Bill Berry to appear in the episode, so the drummer in the episode was a session drummer. Moe's professor was voiced by Dan Castellaneta, the voice actor for Homer Simpson. Formico was voiced by Hank Azaria.