Altaira and Robby November 07 2013
Later the next night, equipment aboard the C57-D is sabotaged, though posted sentries never see the intruder. Adams and Ostrow confront Morbius the following morning. They learn he has been studying a highly advanced native species, the Krell, a race that mysteriously died suddenly 200,000 years before, just as they were on the verge of achieving their crowning scientific triumph.
In a Krell laboratory Morbius shows Adams and Ostrow a device he calls a "plastic educator", a device capable of measuring and enhancing intellectual capacity; he uses it to display a three-dimensional, moving thought projection of Altaira. The Bellerophon's captain tried the machine and was instantly killed. When Morbius first used this machine, he barely survived; he later discovered his intellect had been permanently doubled. His increased intelligence enabled him, along with information from a stored Krell library, to build Robby and the other "technological marvels" in his home. Morbius then takes them on a tour of a vast cube-shaped underground Krell machine complex, 20 miles (30 km) square, still functioning and powered by 9,200 thermonuclear reactors.
In response to the sabotage, Adams orders a defensive force field fence deployed around the starship. This proves useless when the intruder returns undetected and murders Chief Engineer Quinn. Later, Dr. Ostrow is confused by a casting made from one of the large footprints the intruder left behind: its contradictory features appear to violate all known evolutionary laws.
When the intruder returns, the C57-D's crew is prepared. They quickly discover that the creature is invisible. Its roaring image becomes visible as it stands within the fence's force field, further enhanced by the crew's directed high-energy weapons fire, all of which has no effect. Several of the crew are killed during the battle, including Astrogator Jerry Farman. Back in the Krell lab, Morbius is startled awake by Altaira's screaming; at that same instant, the large creature suddenly vanishes from the C57-D's landing site.
Later, while Adams confronts Morbius at his home, Ostrow sneaks away to use the Krell educator; he is fatally injured. As he lay dying, Ostrow explains to Adams that the Great Machine was built to materialize anything the Krell could imagine, projecting matter anywhere on the planet. However, with his dying breath, he also says the Krell forgot one thing: "Monsters from the Id!" When confronted by Adams, Morbius counters by pointing out there are no Krell still alive. Adams pointedly asserts that Morbius' subconscious mind, expanded by the "plastic educator", can now access the Great Machine, recreating the Id monster that killed the original expedition; Morbius refuses to accept this conclusion.
After Altaira declares her love for Adams in defiance of her father's wishes, Robby detects the creature approaching the house. Morbius commands the robot to kill it, but Robby knows it is a manifestation of his master. His programming to never harm humans comes into conflict with Morbius' command, and Robby shuts down. Powered by the Great Machine, the creature melts through the indestructible metal doors of the Krell laboratory where Adams, Altaira, and Morbius have taken refuge. Morbius finally accepts the truth: the creature is an extension of his own mind, "his evil self". He is fatally injured trying to stop the creature, which then disappears. Morbius directs Adams to activate a floor switch (a Morbius self-destruct mechanism) and warns them that the Krell furnaces will now overload; they must be 100 million miles away within 24 hours.
From deep space, with the C57-D safely on course back to Earth, Adams, Altaira, Robby, and the rest of the crew witness the destruction of Altair IV on the ship's viewscreen.