5. There's Wally!
Wally, or Waldo as he is better known in the United States has frustrated young and old alike for generations with his sneaky ways. His books regularly appear in Simpsons Episodes, often frustrating Homer despite the fact that unlike in real life, Waldo is pretty plain to see. Waldo makes a physical appearance in the episode Barts comet in the sixth season. When the residents of Springfield run into Flanders bomb shelter to prepare for the comet you can catch a glimpse of Waldo squeezed in there with the rest of the Springfield residents. He also walks past The Simpsons window in an episode when Homer is attempting to locate him on the side of a cereal box.