Thirteen years after the show had finished production, a TV-movie titled: "The Jungle Movie" was produced by Nickelodeon and most of the show's original crew as a belated conclusion to the series.
Sally's Comet (S01E16b)
Arnold and Gerald need to collect 50 cereal boxtops for a free telescope.
Weighing Harold (S04E07b)After hearing Sid and Stinky talk about how fat he is, Harold goes on an advertised weight loss cruise for kids. Only he somehow instead gains weight on the cruise and comes home even fatter. Arnold then decides to help Harold lose the extra weight.
The Jungle Movie
Eugene has an allergic reaction to pitaya fruit and remains bloated for the duration of the movie.
Harold also appears stuffed after filling up at the buffet on the boat.