Waldo

Waldo is a man who lives in Springfield. He has his own series of books where you try to find him somewhere in the pictures.

History
When Otto moved into 742 Evergreen Terrace he asked Marge if they had any Where's Waldo? books and they didn't.

When Springfield was threatened by a comet he was seen in the Flanders' bomb shelter.

Later when Homer was trying to find a picture of him on a cereal box he walked past the Simpsons' kitchen window.

Non-canon
Bart looks at his book Find Waldo, Yet Again. One page of the book features Waldo standing alone on an empty beach, which prompts Bart to remark, "He's just not trying anymore."

Behind the Laughter
is the main character in the series "Where's Waldo?".