GLaDOS (Genetic Lifeform and Disk Operating System) is a fictional character from the video game series Portal. The character was created by Erik Wolpaw and Kim Swift and voiced by Ellen McLain. GLaDOS is depicted in the series as an artificially superintelligent computer system responsible for testing and maintenance in the Aperture Science Computer-Aided Enrichment Center in all titles. While GLaDOS initially appears in the first game to simply be a voice that guides the player, her words and actions become increasingly malicious as she makes her intentions clear. The second game, as well as the Valve-created comic Lab Rat, reveals that she was mistreated by the scientists and used a neurotoxin to kill the scientists in the laboratory before the events of the first Portal. She is apparently destroyed at the end of the first game but returns in the sequel, in which she is supplanted by her former intelligence dampener and temporarily stuck on a potato battery, while her past as the human Caroline is also explored. The inspiration for the character's creation extends from Wolpaw's use of a text-to-speech program while writing lines for the video game Psychonauts. Other game developers working on Psychonauts found the lines funnier as a result of the synthesized voice. GLaDOS was originally intended to be present solely in the first area of Portal; she was well received by other designers and her role was expanded as a result. Play testers were motivated to complete tests in the game due to her guidance. While the game was initially designed with other characters, they were later removed, leaving GLaDOS as the only character players encounter. The physical appearance of GLaDOS went through several designs, one of which featured a large disk below her. McLain imitated dialog read aloud by a speech synthesizer with her own voice, which was then processed to sound more robotic, and performed songs in character during the closing credits of both entries in the series. "Still Alive" became hugely successful, notably appearing in the Rock Band game series, and has been a popular song for YouTube users to cover. GLaDOS later appeared in The Lab and Lego Dimensions. GLaDOS received critical acclaim from critics and gamers alike, some of whom called her narcissistic, passive-aggressive, sinister, and witty. IGN considered her one of the greatest video game characters, particularly among those created in the 2000s. Universally praised for her contributions to the caliber of Portal's narrative, GLaDOS received multiple awards for being the best new game character in 2007 from GameSpy, GamePro, and X-Play. A number of publications listed her as one of the all-time greatest video game villains, including IGN and Game Informer, both of which ranked her first. She has been the subject of significant critical analysis from both journalists and game developers, who have compared her to other villainous computer systems in fiction, including HAL 9000 from 2001: A Space Odyssey and SHODAN from System Shock, with GLaDOS meeting the former in Lego Dimensions. Source: Wikipedia (en)