Read more about Colossal Boy at: Wikipedia

Official Site: DC Comics

Gim Allon, also known as Colossal Boy, Leviathan, and Micro Lad, is a superhero appearing in books published by DC Comics, primarily as a member of the Legion of Super-Heroes in the 30th and 31st centuries. Created by writer Jerry Siegel and artist Jim Mooney, the character first appeared in Action Comics #267 (August 1960).

He has gone by a variety of superhero names over the past several decades, although originally (and most commonly) Colossal Boy. His name's similarity to the standard Israeli surname Allon led writer Paul Levitz in 1980 to identify the character as Jew.

In the 1990s, the entirety of the Legion of Super-Heroes were changed in what was referred to as a "reboot" of those characters' continuity, including Allon. Later on, these superheroes were again rebooted in what has been referred to as the "threeboot" of the Legion of Super-Heroes.

Gim Allon was mutated by a radioactive meteorite, gaining the superhuman ability to increase his size. His superhero codename became Colossal Boy. With his parents' blessing, he joined the Legion of Super-Heroes, becoming a member in good standing. He had an unreciprocated crush on fellow Legionnaire Shrinking Violet; this crush was only returned when Violet was replaced by a shapeshifting impostor, a Durlan named Yera. The two were married; when the deception was exposed, he discovered that he was still in love with Yera, and they remained married. For a time, Colossal Boy's mother Marte Allon was the President of Earth.

Colossal Boy has not been a contender in any CBUB matches.