
(By way of comparison, Robby cost roughly the same, proportional to total budget, as the massive 27-ton, 12 meter-diameter, rotating centrifuge set built for Kubrick's 2001: A Space Odyssey, which cost US$750,000 against a total budget of around US$11 million). With reported costs ranging from $100,000 and $125,000 (equivalent to at least $US1.1 million today) it was, proportional to total budget, one of the most expensive single film props ever created up to that time, which represented nearly 7% of the film's total budget of US$1.9 million. However, this did not come cheap: As with every aspect of the production of Forbidden Planet, MGM spared no expense on Robby's design and construction. The robot's groundbreaking design and dazzling finish represented a radical advance on the conventional "walking oil-can" depictions of robots in earlier features and film serials, and the only previous film robot of comparable style and quality was the "Menschmaschine" created for Fritz Lang's Metropolis (1927). These concepts were refined by production illustrator Mentor Huebner and perfected by MGM staff production draughtsman and mechanical designer Robert Kinoshita. Robby was designed by members of the MGM art department and constructed by the studio's prop department The design was developed from initial ideas and sketches by production designer Arnold "Buddy" Gillespie, art director Arthur Lonergan, and writer Irving Block. Ostrow, when he is mortally wounded near the end of the film. Robby only carries one person during the film, the Earth starship's Dr. Hollywood purposely, and misleadingly, depicts Robby in the film’s advertising posters as a terrifying adversarial creature carrying a seductively posed unconscious maiden (Altaira), but no such scene is in the film and the images do not reflect in any way Robby's benevolent and intelligent character. One of the laws is a rule against harming or killing humans this becomes an important plot point near the conclusion of the film when Robby refuses to kill the Id monster, recognizing the invisible creature to be an alter ego/extension of Dr. Morbius. Morbius programmed Robby to obey a system of rules similar to Isaac Asimov’s Three Laws of Robotics as expressed in I, Robot (1950).

He is instructed by Morbius to be helpful to the Earthmen and does so by synthesizing and transporting to their landing site 10 tons of "isotope 217", a lightweight though still effective replacement for the requested lead shielding needed to house the C57-D’s main stardrive to power an attempt to contact Earth base for further instructions. Robby exhibits artificial intelligence, but has a distinct personality that at times exhibits a dry wit. In this context Robby is analogous to Ariel, a spirit enslaved by Prospero. The film’s plot appears loosely based on William Shakespeare’s play The Tempest (1610), with the planet Altair IV standing in for Shakespeare’s remote island and Dr. Morbius for Prospero. Robby is a mechanical servant that Morbius has designed, built, and programmed using knowledge gleaned from his study of the Krell, a long-extinct race of highly intelligent beings that once populated Altair IV. The story centers on a crew of space explorers from Earth who land their starship, the C57-D, on the planet Altair IV, ruled by the mysterious Dr. Morbius. Robby the Robot originated as a character in the 1956 MGM science fiction film Forbidden Planet. science fiction novel series by Victor Appleton II.

In Tom Swift on The Phantom Satellite (1956), it is also the name given to a small four-footed robot designed by Tom Swift Jr., the boy inventor in the Tom Swift Jr. The name is also used in Isaac Asimov's short story " Robbie" (1940) about a first-generation robot designed to care for children. In a pulp magazine adventure The Fantastic Island (1935), the name is used for a mechanical likeness of Doc Savage used to confuse foes. The name "Robbie" (spelled with an "ie") had appeared in science fiction before Forbidden Planet.
