Colu is home to a green skinned humanoid life form known as the Coluans. They are one of the most advanced species in the universe, with technological and scientific advancements dwarfing those of other planets.
The government was organized so that the populace was governed by highly advanced computers. Over time these machines became corrupt and treated the people as slaves -- they became known as the Computer Tyrants.
Colu is the birthplace of the Dox family, whose legacy lasts well beyond the 31st Century. The most famous representatives of Colu are the world-conqueror android known as Brainiac, his adopted humanoid son, Vril Dox (aka Brainiac 2) and 30th century resident, Querl Dox (aka Brainiac 5) of the Legion of Super-Heroes.
Mega (Brainiac's homeworld) is a planet some where in outer space. Millions of inhabitants were all killed in cataclysmic atomic wars, however one man survived, (along with a handful of others, as it would soon be discovered) the brilliant Doctor Hecla, who built the android Brainiac, to travel to Earth and capture specimens from every species on Earth, so that Mega can be repopulated.
The Megans had apparently developed some sophisticated technology. They developed a Hyper-Ray that was capable of shrinking any object it touched, and an Ultra ForceShield, which is an impenetrable force field.
The first time Brainiac's planet is actually called 'Colu' is unknown.
The New Adventures of Superman (1966):