Continuity mistake: Ms. Krabapple takes the cellular devices from the children in her class and puts them in a Laramie Cigarette box. She dumps the box into a desk drawer filled with frogs. A few seconds later there is a shot of the class from her point of view with all of their cellular devices on their desks. (00:03:00 - 00:08:15)
Continuity mistake: The size of the smiley face on Krabappel's mug keeps changing between shots. (00:04:50)
Continuity mistake: While Edna is holding the "Goddess Bar", her shirt sleeves are pink like her pyjamas, but in the next shot, she is wearing her usual green outfit.
Answer: Willy referred to an encounter he believed he had with actual aliens, while Wiggum thought he was referring to the arcade game.