A tiny green alien who works for "The Center" as M.O.M.'s personal secretary, often seen flying on his mini hovercraft. He is a powerful idolizer of Martin and in one episode, it was revealed that in his room, he even had a picture of Martin, making him the "crazed fan of the show" type character. His role is generally a supportive one; he pops up anytime during a mission to give Martin, Diana and Java valuable information, usually startling them in the process and he does analysis on slime or fabric samples sent by Martin- but when he is at the mission. He won't help Martin and the gang on a mission directly unless forced. In the second season, Billy was revealed to have once been a great alien warrior, known as Ganthar, on another planet, but gave up violence for good- when Martin asked why a planet on Billy's list of hologram worlds was blue, it was said by M.O.M. that that was the world which changed Ganthar into Billy, which is the reason he doesn't go on missions with the other three agents. He arrived on Earth in the Roswell UFO Incident in 1947.Billy recently adopted a human disguise—the "B.S. 1000"— to be with Martin and Diana at their school. A few episodes in season 3 hinted that he liked Diana, such as in one of the Christmas episodes he invited her under the mistletoe and actually went on a friendly date with her. It is revealed in season one episode "Revenge of the Doppelganger" that Billy was once a super model on his home planet. This might be true, since he was a powerful, fearsome and might have been popular with his people. Voiced by Samuel Vincent.