Continuity mistake: When Burns first shows the team the nerve tonic, the "&" on the 'Brain & Nerve Tonic' label is facing backward, but as Burns pulls it away it faces forward. Then as he moves it around as he's talking, the "&" switches between facing forward and facing backward again. This happens all in the one shot.
Trivia: In celebration of this episode's 25th anniversary, Homer Simpson was inducted into the Baseball Hall of Fame in Cooperstown, NY, complete with an exhibit highlighting the episode.
Answer: Willy referred to an encounter he believed he had with actual aliens, while Wiggum thought he was referring to the arcade game.