Waldo is a hidden character in Fleeing the Complex.
Finding Waldo is one of the sidequests in the game. He can be found in the Yard of The Wall during the "Convict Allies" ending, during the last choice screen. He is hiding behind a rock. Finding him will earn you a medal.
This sidequest is based on a popular series of books starring the titular character Waldo, also known as Wally. The books consist of a series of detailed double-page spread illustrations depicting dozens or more people doing a variety of amusing things at a given location. Readers are challenged to find Waldo hidden in the group. The character of Waldo has appeared in a similar way in various other media, like the movie Naked Gun 33⅓: The Final Insult.