Годзилла мен Франкенштейн: Тұжырымдамасы құлаған шайқас

In 1964, Henry Saperstein approached Toho to co produce Frankenstein vs. Godzilla with his company United Productions of America. The story would pit Godzilla against a giant Frankenstein Monster. Takeshi Kimura was hired to write the screenplay with Jerry Sohl and Reuben Bercovitch writing the story and synopsis for the film. The story dealt with the heart of the original Frankenstein monster becoming irradiated and growing into a giant Frankenstein Monster. Afraid the giant would start eating people, Godzilla would be awakened from slumber in the Kurile Trench by the JSDF and goaded into a fight with the Monster in hopes of destroying him. The story would end with natural disasters defeating the monsters as Godzilla disappears into a raging river flow, and the giant Frankenstein Monster disappears into magma caused by an erupting volcano. Toho was not fond of the logistics of the story, so the idea was dropped. When the Godzilla series would resume later that year, Mothra was brought in as Godzilla's next opponent for the film Mothra vs. Godzilla instead. In 1965, Toho and UPA would revive the project into this film. A new dinosaurian opponent named Baragon was created to replace Godzilla as Frankenstein's opponent and the script was slightly altered. Most of the concepts from the original story treatment were retained in this version, such as the irradiated heart of the Monster, the Monster's relentless pursuit of food and a natural disaster defeating the Monster during the climax. In addition, most of the characters from the original story, such as research scientist Dr. Bowen (played by Nick Adams), would be retained. In the American version, Jerry Sohl would get credit for a synopsis and executive producer Reuben Bercovitch would get credit for the story. Koji Furuhata earned the role of Frankenstein through an open audition. Furuhata wore green contact lenses to emulate a Caucasian look, a flat head prosthetic and brow resembling Jack Pierce's Frankenstein Monster design and large shirts and loincloths. Honda had originally wanted to explore more of the science gone wrong theme, but was forced to change the story in the middle to reach a climactic monster battle. Nick Adams delivered all of his lines in English, while everyone else delivered their lines in Japanese.

Henry G. Saperstein had requested an alternative ending for the international release in which Frankenstein battled a giant octopus, who eventually defeated Frankenstein by dragging him into a lake. This resulted in the cast and crew being reassembled after principal photography and post production had wrapped, as well as building a new set and building a new prop to represent the giant octopus from foam, latex and sawdust initially moulded over a wire frame for support during construction. Despite filming the new ending, Saperstein ended up cutting it regardless because he believed the giant octopus "wasn't that good". When the film was in production, trade magazines listed this film's title as Frankenstein vs. the Giant Devilfish. Honda had stated that the reason why the giant octopus ending was initially requested was because the American co producers were "astonished" by the giant octopus scene in King Kong vs. Godzilla and wanted a similar scene in this film. Honda also confirmed that various endings were shot, stating: "In fact Mr. Tsuburaya had shot five or six final scenes for this film. The infamous giant octopus is only one of these endings." Honda also expressed that the alternate ending was never intended to be released on the Japanese version, stating: "there was never any official plan to utilize the sequence; but an alternative print with that ending was accidentally aired on television surprising many Japanese fans because it was not the ending they had remembered from the original theatrical release."

The film was released in Japan on August 8, 1965, two days after the 20th anniversary of the Hiroshima bombing. The film grossed ¥93 million during its Japanese theatrical run. The film was released theatrically in the United States as Frankenstein Conquers the World on July 8, 1966 by American International Pictures. This version was dubbed in English by Titan Productions and restored Adams' original English dialogue. In November 2017, Toho released the film on Blu ray in Japan. This release also includes an HD remaster of the international version. In September 2022, The Criterion Collection announced to have acquired the Japanese version to stream on their site the Criterion Channel.

The following year, Toho released a sequel titled The War of the Gargantuas, also co produced with UPA. In the film, pieces of Frankenstein's cells mutate into two giant humanoid monsters: Sanda (the Brown Gargantua) and Gaira (the Green Gargantua). The former is a benevolent and peace loving creature, while the latter is murderous and savage. Apart from a reference to a severed hand, UPA obscured all references to Frankenstein in the American version and the names of the monsters were changed to the Brown Gargantua and the Green Gargantua. Gaira and Sanda would later appear in two of Toho's tokusatsu series, Ike! Godman and Ike! Greenman, before remaining absent for over 40 years, with Gaira making his latest appearance in a 2008 Go! Godman special.