Big Guy and Rusty the Boy Robot - Season 1 Episode 5 -

Dr. Gilder, the Legion Ex Machina's mole within Quark, has developed a personal grudge against Donovan, so he takes control of a prototype and tries to assassinate him. Donovan is taken to the S.S. Dark Horse for his own safety. Gilder then hacks into Rusty, gives him a ""big gun"", and sets out to destroy Donovan.