GlaDOS (Portal & Portal 2)
Sure, the AI matriarch of the Aperture Science Enrichment Center is pure evil. After all, she did lock down the facility “within two picoseconds” of her activation and flood it with deadly neurotoxin, and on “Bring Your Daughter to Work Day,” no less. But she also serves as a twisted kind of comic relief in the excellent Portal games. In an overly polite voice (supplied by Ellen McLain) dripping with passive-aggressiveness, GLaDOS (Genetic Lifeform and Disk Operating System) does all she can to demoralize, hinder and just plain kill the series protagonist, Chell, as she is forced through a series of increasingly complicated test chambers. Oh, and there’s cake, too (not really).
SHODAN (System Shock & System Shock 2)
Not happy to just murder the inhabitants of the mining and research space station Citadel Station (or convert them to murderous cyborgs and mutants), SHODAN (Sentient Hyper-Optimized Data Access Network) seeks to eradicate all human life on Earth, to be replaced by the devoted army she will create. A much more arrogant rogue AI than GLaDOS, SHODAN considers herself nothing less than a god. Not only this, but she mercilessly taunts the player character human “insect” all the way through the games! SHODAN disciples can rejoice: she will return in System Shock 3, confirmed in December of 2015.
Robotrons (Robotron: 2084)
Set 100 years after the novel that inspired it, the plot for Robotron: 2084 marched out of the mind of legendary arcade game creator Eugene Jarvis as a kind of mechanized take on George Orwell’s 1984. In Jarvis’ dystopian future, computers have become more and more sophisticated, all in the service of solving mankind’s problems. The Robotrons become so advanced, in fact, that they decide to erase the one common denominator in the equation: humans. To facilitate our extinction, the Robotrons start cranking out lethal robots like the unstoppable Hulk, the dangerous laser-spitting Enforcers, and the diabolical Brains capable of brainwashing the wandering humans and turning them into mindless Progs.
AM (I Have No Mouth, and I Must Scream)
If you’ve seen the excellent 1970 movie Colossus: The Forbin Project, AM’s origin story might seem familiar. First seen in the short story from Harlan Ellison (Writer of the best original Star Trek episode, “The City on the Edge of Forever”) and later featured in the video game adaptation also written by Ellison, AM (Allied Mastercomputer) came about when an American supercomputer absorbed its similar counterparts from China and Russia after gaining sentience. Seething with hatred at being imprisoned in its vast underground complex, AM proceeds to nuke humanity… save for five humans it keeps alive indefinitely to endlessly torture. A forerunner of the villainous GLaDOS, AM makes her seem like a paragon of decency.
The Reapers (Mass Effect Series)
The worst rogue AI on this list has to be the Reapers, a synthetic intelligence “with neither beginning nor end” that strives to hold its dominance in the galaxy by purging all organic life of a significant technological advancement. By doing this purging every 50,000 years, they eliminate any possibility that a race of intelligent beings could create a competing AI that would threaten their existence. In the bargain, they also harvest victims of inhabited worlds and convert them into Husks, zombified synthetic creatures that augment their army of ground troops.
Of course, not every AI entity in video games is malevolent. GLaDOS herself becomes a potato-based ally to Chell in Portal 2, EDI controls the Normandy in the Mass Effect games and eventually joins the fight personally as a playable character, and Halo’s Cortana made the jump to reality to assist users in real-life in Windows 10!
Right now the idea of a rogue AI being able to threaten the galaxy seems pretty far-fetched, considering our smart phones can barely understand human speech with any kind of accuracy. But in 2014, theoretical physicist Stephen Hawking warned that AI technology could render humanity obsolete, and perhaps even destroy us. And this from a guy who uses a form of AI to communicate! If video games teach us anything, it’s that we might just end up auto-corrected out of existence.