It's common to see auctions of actor's memorabilia, but Bonhams is going one better by auctioning the actor himself. Part of next month's Out of this World Sale, the auction house is accepting bids for the original Robby the Robot prop/costume from the Metro-Goldwyn-Mayer (MGM) 1956 sci-fi feature Forbidden Planet, along with his futuristic hover car, control panel, and assorted accessories.

Before a certain cybernetic comedy pair stole the show in 1977's Star Wars, the single most iconic robot in Hollywood history was Robby the Robot. Designed for MGM by Robert Kinoshita, Arnold Gillespie, Irving Block, Mentor Huebner and Arthur Lonergan, and constructed in the studio workshops, Robby has had a surprisingly long history in films and is even unique in having an actor's page on IMDB.

Robby the Robot was originally built to play the mechanical butler and bodyguard for the mad scientist Morbius (Walter Pidgeon) and his daughter Altaira (Anne Francis) in the Forbidden Planet . The story takes place on the planet Altair 4, where the pair are visited by Commander JJ Adams (Leslie Nielsen) and his crew from the space cruiser C-57D in the year 2057. Subsequently, Adams becomes involved in the mystery behind the deaths of Morbius's original companions, the fate of a long-dead super race called the Krell, and the appearance of a murderous, invisible "Id" monster of growing power and malevolence.

The script was based loosely on Shakespeare's The Tempest, with Robby as a robotic version of the ethereal sprite Aerial and Morbius as a futuristic Prospero. Robby's appearance was notable not only for his laconic, deferential humor, but also because he was the first cinematic robot who wasn't cast as the monster or a henchman. In addition, Robby was programmed with Isaac Asimov's famous Three Laws of Robotics, which meant he was programmed to obey all orders, but not to harm human beings – a conflict that causes him to have an electronic nervous breakdown during the film's climax.

Forbidden Planet was MGM's first major science fiction film. Robby cost US$120,000 to build (US$1.2 million in today's money) and was constructed out of vacuum-form Royalite plastic, acetate, and aluminum with rubber hands, a Perspex transparent "head" and a pair of men's size 10.5B black leather loafers inside the feet for the actor wearing the 100 to 120 lb (45 to 54 kg)) prop/costume, which was articulated like a suit of armor.

But Robby was more than a suit. He included seven war-surplus electric motors to power his mechanical "scanners" and "brain," plus a "mouth" made of blue neon tubes run by a 40,000 Volt power source run via a cable out of the robot's heel or onboard batteries.

Sitting so close to so much voltage was just one example of how hard Robby was on the actor inside him. Though Robby stands over six feet tall, the actor had to be very short to look out through the "mouth" with his face blacked up with matte black makeup to prevent being seen by the camera. The weight of the three parts of the robot were carried on a flying harness on the actor's shoulders and a special frame was built to allow him to rest between takes. Even then, Robby could only walk on a completely flat surface with actor unable to see his feet and after a near tumble, the actor Frankie Darrow had to be replaced by Frank Carpenter because he was too shaken up to continue.

Another important factor in Robby's success is that he was designed to be portable, breaking down into three parts and placed in specially designed crates along with his effects control panel. After Forbidden Planet opened, Robby attended the premiere at Grauman's Chinese Theater and then toured the country on a promotional tour. After that, Robby starred in the feature The Invisible Boy before embarking on a decades-long career, appearing in television programs like The Thin Man, The Twilight Zone, Columbo, Lost in Space, and The Addams Family, as well as various films, science fiction conventions, and charitable events up to this day.

Unfortunately, MGM didn't take very good care of Robby and the prop was in poor shape when he and his car were sold to Jim Brucker in 1970 for display at Movie World/Cars of the Stars. In 1979, Robby was bought by filmmaker and special effect designer Bill Malone, who had already built a full scale reproduction of the robot from the original blueprints. Using his expertise, Malone restored the badly deteriorated bot, including casting new rubber hands and Perspex dome, which had rotted and yellowed respectively.

According to Bonhams, Robby is now fully operational, though the car, which is based on a Jeep chassis, no longer functions due to MGM cannibalizing the steering system. Along with the robot and vehicle, the sale includes an alternative head built for a Twilight Zone episode, a pair of interchangeable claws that were part of the original design, the resting frame, control panel, and packing cases.

The Out of this World Sale runs through November 21. No price estimate has been released.

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