Cosmo Julius Cosma is one of the main protagonists on the show. He is one of Timmy Turner's fairy godparents alongside his wife, Wandaand his son, Poof. Cosmo is one of the dumbest characters on the show, rivaled only by Timmy's Dad, and his ideas are what often lead Timmy into trouble. He is sometimes a bit over-emotional. Cosmo is voiced by Daran Norris in the cartoon, who also voiced the CGI (3D) version of Cosmo in the live action "Fairly Odd Movie". A humanized version of Cosmo also appeared in the live movie, played in live action by Jason Alexander.
Cosmo appears as a character that must be photographed.
Cosmo appeared alongside of Timmy in Nicktoons Unite!. Cosmo and Wanda function as the weapons for Timmy in the game. Because of Mr. Crocker who was stealing all the fairy energy, they couldn't use their powers to a maximum. When Cosmo and Wanda would have enough energy they could fulfill one wish of Timmy, so he had a new ability. When they beat Professor Calamitous their powers returned. Throughout the whole game it is assumed by the others that Cosmo and Wanda are holograms.
Cosmo also appears in the loading screen, flying towards Wanda.
Cosmo appears as a character, aiding Timmy in races.
Cosmo appears again in Nicktoons: Battle for Volcano Island]] where he, along with Wanda, aids Timmy in the battle for Volcano Island. Cosmo functions as Timmy's melee attack in the game. He transforms into a hammer so Timmy can smash with it. Cosmo and Wanda can't fully use their power because The Mawgu was blocking it.
Cosmo appears in Nicktoons: Attack of the Toybots as the weapon of Timmy once again. He again transforms into a hammer so Timmy can attack with him. Unlike Cosmo, Wanda doesn't do anything. Both of Cosmo and Wanda's fairy magic had been drained because they ate too much Krabby Patties and farted their magic out.