Mogo... doesn't socialize. His sheer size and gravity well will wreck havoc with any other planets, causing unimaginable destruction.
Mogo's origins and introduction to the Green Lantern Corps are currently unknown. His current role is to provide a training and relaxation facility, his skill at altering his appearance providing an invaluable asset.
One of the few tales known about Mogo is that of Bolphugna the Unrelenting.
Bolphugna was a creature of violence who had built a reputation from numerous fights he had won. He intended to beat the most feared and mysterious being of them all... the Green Lantern known as Mogo.
The search for his quarry led him to an Earth type planet, devoid of any signs of intelligent life. Bolphugna called for the Green Lantern to face him. Receiving no response, he searched the planet for the Green Lantern.
Bolphugna's task was made all the more difficult by the fact that no one had any information as to what Mogo actually looked like. This would not stop him. Bolphugna spent years searching for the Green Lantern, examining plants, animals and insects. He grew more methodical in his search, surveying and drawing maps of the terrain. Although Bolphugna could find no intelligent life, he noted the forests seemed to be groomed in strange patterns, with large tracts of open land.
One night, entirely frustrated by his search, Bolphugna spread the maps out in front of him. Placing the ends of the maps together, the strange patterns of the trees made out the symbol of the Green Lantern Corps. Bolphugna quickly realized the very planet he was standing on was the Green Lantern known as Mogo. For the first time ever, Bolphugna the Unrelenting... relented. He ran to his starship, took off, and has not been heard of since.