In the 1951 science-fiction film The Day the Earth Stood Still, the robot’s name is Gort.
Gort is the powerful robot accompanying Klaatu, an extraterrestrial visitor who comes to Earth with a warning about humanity’s use of atomic weapons. The film was directed by Robert Wise and is based on Harry Bates’s 1940 short story Farewell to the Master. Gort’s famous command, “Klaatu barada nikto,” became one of science fiction’s best-known phrases.
Gort is relevant to Pandora’s Box through the 1951 film’s alternate release title, The Day the Earth Stood Still (UFO), which is sometimes confused with other “Pandora” media listings, but it is not a Pandora adaptation. This question identifies a separate well-known science-fiction title to avoid that confusion. Klaatu is the visitor; Gort is the robot who protects him and demonstrates the consequences of disobedience.