He explains to Alice that the source of his energy lies in his cave, where he takes her and attempts to woo her before being interrupted by the Professor's broadcast.

Immediately after this, the Great One contacts him, angry at him for thinking up the plan to keep the girl and accusing him of bearing free will in violation of Ro-Man law.

The Great One continues the genocide with Cosmic Q-Rays, which cause prehistoric reptiles to appear; and psychotronic vibrations, which "smash the planet Earth out of the universe".

Suddenly, Ro-Man, his arms raised in a threatening manner after having just arrived on Earth, walks out of his cave directly toward the audience.

Twenty-five-year-old writer/director Tucker made Robot Monster in four days for an estimated $16,000 (equivalent to $180,000 in 2023),[5] although film journals from the time reported that it cost $50,000.

[9] Robot Monster's very low budget did not allow for a robot costume as first intended, so Tucker hired his friend Barrows, who had made his own gorilla suit, to play Ro-Man; Tucker then added a space helmet similar to those used in Republic serials such as Radar Men from the Moon.

[4] Robot Monster is similar in its plot to Invaders from Mars, released a month earlier by 20th Century Fox.

[11] The film was preceded in theatres by Stardust in Your Eyes, a one-reel 3D monologue by comic/impressionist Trustin Howard, performing under his stage name "Slick Slavin.

[13] Producer Al Zimbalist later told The New York Times that shooting the film in 3D (which involved using another camera) added an extra $4,510.54 to the budget.

(1940), Lost Continent (1951), and Flight to Mars (1951);[5] a brief appearance of the Rocketship X-M (1950) spaceship boarding; and a matte painting of the ruins of New York City from Captive Women (1952).

[17] Ordung stated that Bernstein scored the film with an eight-piece orchestra, and Capitol Records expressed interest in producing an album.

[21] It was originally released with the Three Dimension Pictures short Stardust in Your Eyes, starring nightclub comedian Trustin Howard as Slick Slavin.

[5] The December 1952 review in Variety noted, "Judged on the basis of novelty, as a showcase for the Tru-Stereo Process, Robot Monster comes off surprisingly well, considering the extremely limited budget ($50,000) and schedule on which the film was shot".

[24] In December 1953, the Los Angeles Times reported that "theater men" considered the film "one of the top turkeys of the year.

"When I was refused a job – even as an usher", Tucker wrote, "I finally realized my future in the film industry was bleak."

[citation needed] Selena Royle, an MGM stock player, had a durable film career beginning in 1941, but it ended in 1951 when she was branded a Communist sympathizer.