Cosmo The Spacedog's History
Cosmo is a former test animal of the Soviet Space Program. He was launched into Earth's orbit as part of an experiment but he drifted off into space during the 1960's, arriving in Knowhere and at some point being mutated, he eventually came to serve as the station's security chief.
Cosmo met a distraught Nova shortly after he witnessed Suspensor turn into a zombie. He tells Nova that he's on Knowhere, a city right inside the severed head of a giant Celestial. Beings from all over the universe come to Knowhere, waiting for the end of the universe. Right now, the city's population had to go into hiding right after the Luminals brought something in a big box. Worldmind then informs Rider that he had deciphered the writing on the wall, which is a countdown to a timer.
Suspensor attacks them and he is forced to kill her in self defense only to have her allies Cynosure, Crater and Discharge blame him for her death. Unable to fight the three aliens, as he retreats he makes a discovery of a talking dog. However, Cosmo gained Nova’s trust and friendship, and the two set out to find the fiend responsible for all the recent deaths on Knowhere.
Cosmo brought Nova up to speed on when the events started, and the Xandarian Worldmind added any data he had at his disposal. Cosmo was mainly concerned with the safety of the remaining citizens of Knowhere who were safely hidden away in a dimensional envelope he wore on his collar. It was not long before Cosmo and Nova were ambushed by more zombies including the surviving members of Suspensor's former team, the Luminals, and determined that the creature known as Abyss was behind the mayhem. Together, they fought off the attacks, sealed Abyss inside his prison.
Cosmo then charted a course to the birthplace of the Phalanx, the planet Kvch, in hopes that he can find a way to cure himself of the Transmode Virus that is slowly killing him. Then alarms were triggered when a murderous Gamora and Drax, now under the control of the Phalanx, slaughtered many residents in search of Nova. Cosmo arrived too late to stop them before they could follow the same path as Nova through the Continuum Cortex.
The true nature of the Fault began to reveal itself and the corrupted beings of the Cancerverse began their invasion. The Guardians of the Galaxy allied with Thanos to stop the evil Lord Mar-Vell. In the end, the team disbanded, losing Adam Warlock, Phyla-Vell, Drax and their leader Starlord. But before he died, Starlord left Cosmo with a task collect the greatest heroes in the universe to form a band of Annihilators, the team Starlord believed was what the Guardians of the Galaxy should have been. Cosmo one by one convinced the Silver Surfer, Gladiator, Beta Ray Bill, Quasar and Ronan the Accuser to team up and protect the universe together, as was Starlord's final wish.
He was last seen injured, after Captain Skaarn's takeover of Knowhere. Skaarn had poisoned Cosmo and shot him with something that dampened Cosmo's psychic telepathy. Using the Nova Force, the young Nova tried to push the poison out of his body. In the process, he found the foreign body inside of the psychic dog that disrupted his powers, and thus, saving him.