Game Machine Man is one of the Seven Shadows. He was trapped inside a Rainbow Crystal and reborn inside an arcade champion named Game Machine Joe.
In Episode 21, Jupiter Comes Thundering In, Zoycite extracted the Rainbow Crystal from him and turned him into Game Machine Man, Champion of the Negaverse. His attacks included turning his hand into a mallet or extending wires from his hand. When Lita threw Game Machine Man down, the mark of Jupiter appeared on her forehead. Luna gave her the power to transform into Sailor Jupiter, who disconnected Game Machine Man's circuits with her Jupiter Thunder Crush. As he was getting back up, Luna gave Sailor Moon the power to use Moon Healing Activation, which she used to heal Joe, returning him to normal and destroying the Shadow within him.