Ozzy is a genie from an amp discovered by Kurtz who he grants three wishes. He has a main role in the episode "Music Soothes the Savage Genie". He plays a wish riff on his guitar to grant wishes. He also sings the song "The Next Big Thing" while Mantyz play.
Kurtz then tells him that when he said he wished they were the biggest band in Los Bosmos, he meant he wished they were the greatest band in Los Bosmos. Ozzy returns them to normal size and grants their second wish. He then grants Kurtz third wish during a soundclash as he wishes Freefonix no longer had 13th note powers and in doing so transfers their powers to Mantyz. Ozzy then returns to his amp.
Freezbone gets hold of Ozzy's amp and has Ozzy grant him three wishes. Freez then wishes that Freefonix had their 13th note powers back and that Mantyz were no longer the greatest band in Los Bosmos. He also makes a wish for Misty. After that Ozzy returns to his amp once again. The only way Freefonix could have stopped Ozzy while still still serving Kurtz was to find an ancient bootleg tape which is the only thing that would return Ozzy to the amp.
His name is most likely a reference to Ozzy Osbourne, lead singer of the band Black Sabbath.