The Legion of Substitute Heroes is a group of fictional characters in the future of the DC Comics universe. The "Subs", as they are often called, are a group of rejected applicants to the Legion of Super-Heroes who banded together, hoping to prove to the Legion that their powers were not as useless as the Legionnaires claimed. They first appeared in Adventure Comics #306 (March 1963). They were depicted as reasonably effective superheroes until Keith Giffen, during his tenure as Legion writer, began depicting the team as something of a joke. The Subs regained some respect when founding member Polar Boy joined the main Legion and a new Legion of Substitute Heroes was formed.