The one known Cosmog is a notoriously free-spirited pokemon, who, despite its extraterrestrial origins, detests being confined in dark spaces – not that any can hold it for long. Its gaseous body can not only slip through microscopic holes in a pokeball's structure, but unlike Abra, it can (and often does) freely simply teleport away. The Aether Foundation, its first known owner on this planet, experimented on it, hoping of producing a ball that could seal it and other extraterrestrials with biology far less compatible with pokeballs than that of Elgyem. These experiments ultimately led to the invention of the Beast Ball, but many scientists have denounced the outcome as imperfect, claiming they could have produced something as effective as a Master Ball, if only their subject had not escaped.
In all likelihood, it was a dangerous encounter with a black hole that made this Cosmog so famously claustrophobic. Its one known trainer, the runaway daughter of the Aether Foundation's president, rescued it at great personal cost, but could never quite solve the challenge of hiding it from public view. Observing her sole pokemon's reaction to a pokeball, she resorted to carrying it in her handbag – or attempting to, anyway, for it appears it spent more time outside said bag than in. Despite understanding the reasons for her secrecy, only when placed alongside other objects could the Cosmog, who she named "Nebby", bear to remain in the bag. And whenever the bag was squeezed, or even jostled in a way that pushed items into it, Nebby inevitably escaped.
The question of that Cosmog's transportation was only resolved when it evolved and gained the strength to protect itself. Whether others exist, and if they share Nebby's aversion to enclosed spaces, is known only to those who explore the sea of stars.
