Trivia / This Island Earth

• The Metalunian mutant's blood was not ordinary fake blood, but actual tomato ketchup, which started to go off under the hot studio lights.
• Completely Different Title: In Germany, the film was released as Metaluna 4 Does Not Reply, while in Japan the film was released as Uchū Suibakusen ("Space Hydrogen Bomb War").
• Creator Backlash: Surprisingly, the cast and crew were heavily divided on the Mutant, considering it became the movie's most iconic character. Rex Reason said that it "didn't have the realism of the rest of the picture," while Jeff Morrow joked that he considered sneaking out of the premiere when the Mutant appeared. Screenwriter Franklin Coen agreed with Reason that the creature "cheapened the whole picture" although he liked its design. Producer William Alland told an interviewer that the Mutant was "one hell of a mess" and "outrageous" (though Coen says that Alland acted quite proud of the Mutant at the time, and enjoyed showing the costume off to reporters and other visitors to the set). Faith Domergue disagreed, saying that the Mutant was "a stroke of genius" and the best part of the movie, an opinion much closer to the fan consensus.
• Prop Recycling: The "picture of a burger" on Exeter's office wall was apparently a stock prop in Universal films. It made another appearance in The Leech Woman (mentioned on that film's Mystery Science Theater 3000 episode as an "original Ray Kroc"). Both movies had the same set designer, Russel A. Gausman.

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