Yuki Tachibana, a withdrawn first grader, is convinced that the fourth floor of his school is home to supernatural creatures that few kids (and no adults) can see and he's worried about a recent influx of new, less friendly creatures and about his ability to perceive the true shape of things waning as he gets older. Most of the other kids mock Yuki, who they think is crazy due to his strange pronouncements and peculiar actions, and, aside from the creatures he sees, his only social interactions are with the school's kindly and open-minded caretaker, a new transfer student named Makoto Suzuki who's allocated the desk next to his and an enigmatic boy named IQ who always wears a box over his head.

Gogo Monster won the Special Award at the 30th Japan Cartoonists Association Award in 2001. The series was published in English by VIZ Media under the VIZ Signature imprint on November 17, 2009. VIZ Media republished the second edition of the manga on July 23, 2024.