Klaatu (The Day the Earth Stood Still)
Klaatu () is a fictional humanoid alien character featured in the 1951 science fiction film The Day the Earth Stood Still and its 2008 remake. The character of Klaatu gained popularity, partly due to the iconic phrase "Klaatu barada nikto!" associated with the character. Michael Rennie as Klaatu 
In the film "The Day the Earth Stood Still," Klaatu, portrayed by Michael Rennie, arrives in Washington, D.C. in a flying saucer alongside Gort, a robotic companion. As a peaceful ambassador from an extraterrestrial confederation, Klaatu presents a device to the American President, intending it to be a gift for studying life on other planets. However, a soldier from the welcoming committee misinterprets Klaatu's actions and shoots him. In response, Gort destroys the surrounding artillery to protect Klaatu. Klaatu is taken to a hospital where he quickly recovers. Realizing that other nations may not be willing to meet him, he assumes the alias "Carpenter" based on the name found on his clothes and suitcase. He befriends Bobby Benson, a boy staying at the same boarding house with his widowed mother, Helen Benson, played by Patricia Neal. Klaatu visits Professor Barnhardt, a renowned scientist portrayed by Sam Jaffe. When Klaatu/Carpenter is brought before Barnhardt, the professor agrees to gather scientists from all nations. He asks Klaatu for a demonstration of power to show the potential threat posed by the extraterrestrial alliance if Earth disrupts the peace in space. Klaatu neutralizes electric power worldwide for 30 minutes, except in places where lives would be endangered, such as hospitals and airplanes in flight. This action is perceived as an act of war. Betrayed by Mrs. Benson's suitor, Klaatu is fatally shot by the U.S. Army. However, before dying, he instructs Mrs. Benson to deliver the message "Klaatu barada nikto!" to Gort, saving her life. Gort retrieves Klaatu's body and revives him. In a gathering of scientists, Klaatu gives an ultimatum: Earth can either join other spacefaring worlds, where peace is maintained through a powerful force of robots similar to Gort, or face destruction. Klaatu departs following his declaration. Keanu Reeves as Klaatu 

The 2008 remake of "The Day the Earth Stood Still" features Keanu Reeves as Klaatu and Jennifer Connelly as Helen Benson. In this version, it is revealed that Klaatu's biology was altered to assume a human form using DNA obtained in 1928. Initially captured by the military, Klaatu manages to escape with Helen's assistance. He meets a man named Mr. Wu, who is actually another member of Klaatu's alien race in disguise. They discuss the fate of humanity and Klaatu initiates a plan involving smaller spheres hidden on Earth to remove animal species, similar to the concept of Noah's Ark. Additionally, Klaatu activates Gort to destroy humanity. Throughout his time on Earth, Klaatu spends time with Helen and her stepson, Jacob, and engages in conversations with Professor Barnhardt. Klaatu ultimately sacrifices his physical form to halt Gort's destructive actions. His spaceship or sphere then departs from Earth. In Reeves' portrayal, Klaatu exhibits minimal emotion, explaining that he is an alien entity residing within a human body. Consequently, he lacks the natural gestures and expressions of humans, appearing more stoic and detached. The filmmakers aimed to depict Klaatu as distinctly different, with a focused and unique perspective on the world. Unlike the original Klaatu, who was unfamiliar with Earth, the remake introduces the presence of another member of Klaatu's race who had been on Earth for decades prior to the events of the film. Analysis 

Science fiction scholar Gary Westfahl writes that Klaatu's planet of origin in the 1951 film must be Mars, citing Klaatu's assertion that his journey covered —the approximate distance between Earth and Mars when the planets are on diametrically opposite sides of the Sun. Westfahl finds the choice of that particular distance to be highly suggestive of intentionality—in his opinion, someone giving a distance at random would be much more likely to give a more round figure, making it implausible that a somewhat-precise figure that also roughly corresponds to the maximum Earth–Mars distance is coincidental. As corroborating in-story evidence, Westfahl points to Klaatu's line about being "neighbours" and a newspaper headline that reads "'Man from Mars' escapes from army hospital!". Moreover, Westfahl writes that portraying Martians as parental figures "is a ubiquitous trope in science fiction", and "It is a tradition that Klaatu fits into quite nicely." Specifically, he finds Klaatu to be an example of the archetype of Martians as positive parental role models, with wisdom to share and stern warnings of follies to hand out—as opposed to e.g. oppressive or dependent parents. Westfahl thus concludes that Klaatu is a Martian both textually and intertextually. References 

Extraterrestrial characters in films
Science fiction film characters
Literary characters introduced in 1940
Film characters introduced in 1951