The Iron Lizards are a series of land-based homing missiles that were designed by The Warden, for the purpose of acting as his prison's security system.
The Warden was the sadistic administrator of a prison located in a remote and nameless country, which Lupin's gang had the misfortune of winding up in. He appears as the main antagonist of episode 25 of The Red Jacket Series, The Coming of the Killer Iron Lizards. Very little is known about the man, how he obtained his position, or even his true name. The only bit of back story that is given is that he was once a children's toy designer. At some point, Fujiko managed to get herself incarcerated within the confines of the penitentiary; The Warden took an immediate liking to the girl and soon became infatuated with her. Fujiko was nothing but disgusted by the man and spurned his lecherous advances. After some manipulation, Fujiko managed to lure Lupin and the rest of the gang to the prison, hoping to be broken out. A mere while later, Lupin, Jigen, and Goemon escaped the prison, followed by three Iron Lizards that contained the men's DNA. After a lengthy chase, Lupin outsmarted The Lizards by luring them back to the prison and having the three crash with one another. The gang managed to escape but not before Fujiko obtained a strand of The Warden's hair and implanted it into an Iron Lizard, successfully using his machine against him. The Warden was last seen running for his life from the Iron Lizard.
The Warden had no need for any but a few guards at his prison; in fact, the prison security seemed extremely poor at first glance. Inmates wandered the halls of the prison, cell doors wide-open, even the front gate was left raised. The Warden had no problem with escapees however, as he was able to keep his prisoners in-line through fear instilled upon them by The Iron Lizards. The Iron Lizards were relatively small, motorized, robotic lizards that were designed to track down predestined targets and explode upon impact. Whenever an inmate arrived, a sample of DNA was taken from their body and inputted into a miniaturized computer located inside The Lizards. The robots were capable of moving at varying speeds, usually a tad bit slower that the speed it's target was moving; this feature was probably intentionally designed by the sadistic warden, as he most likely enjoyed psychologically toying with his victims before disposing of them. Nevertheless, The Lizards were able to move through virtually any terrain (even through aquatic environments), at speeds as great as that of an automobile or speedboat. Even though The Iron Lizards seemed almost unstoppable, there was one fatal flaw to their design: according to The Warden, the only way to stop the robots was to have them collide into each other. Lupin and the gang managed to accomplish this, as they set a trap where they were to wait together in a basket suspended above the spot where The Lizards would meet and obliterate one another.