Is There Only One of Them?

Three panels from the animated show 'King of the Hill' show a woman handing out candy to trick-or-treaters, then greeting them with 'HAPPY HALLOWEEEEEN!', and finally showing the kids looking disappointed as they each only received one piece of candy, with the text '... ONLY ONE??' overlaid. The characters are dressed in Halloween costumes including a ghost, a striped prisoner, and a bat.