Mad computers ("Humanity must be destroyed!")
From the moment we came up with the idea of artificial intelligences, we've wondered what would happen if they turned on us, their creators. At its root, it's a fear of being knocked off the top of the food chain; what if our creations are more intelligent and powerful than us?
Cinema's evil AIs range from malfunctioning machines to malevolent software – but they have one thing in common. They want us dead.
HAL 9000 (2001: A Space Odyssey, 1968)
The computer controlling the spaceship Discovery One is one of Stanley Kubrick's most iconic creations; a softly-spoken, disembodied presence haunting the corridors of the ship. Initially, it seems benign – but a series of minor malfunctions point to something more sinister, prompting the ship's crew to try and shut it down. By that point, it's too late; HAL has decided that the mission is more important than the crew.
You could argue that makes HAL an implacable intelligence rather than a malevolent one, but Kubrick initially leaves an element of uncertainty as to whether HAL possesses genuine emotions or is simply a machine following orders to the last. However, in HAL's final scene, in which it's slowly deactivated by astronaut Dave Bowman, it becomes clear that the computer can feel fear. In a neat touch, the computer's last words as it regresses towards its earliest memories are the words to the song "Daisy Bell" – used by IBM for the first demonstration of speech synthesis.
Skynet (The Terminator, 1984)
We don't know much about what drives the genocidal artificial intelligence from the Terminator films to wipe out humanity – only that after it becomes self-aware on August 29th, 1997, the US military tries to "pull the plug."
Not surprising, then, that it comes to see all people as a threat, not just the ones on the other side. For Terminator 3, the evil AI was reinvented as an intelligent computer virus – and for the benighted Terminator Salvation, it was given a face in the form of Helena Bonham Carter. Which is just one more reason to consign that film to the dustbin of history – the whole point of Skynet is that it's a faceless enemy.
Master Control Program (Tron, 1982)
The sinister cylinder at the heart of ENCOM's mainframe, this megalomaniac program started out life as a chess game – but after it's converted to adminster the mainframe, it develops ambitions beyond the computer world.
It's an interesting variation on the traditional cinematic computer villain; where AIs in film are usually defined by their interactions with our world and with humans, the MCP is depicted as a god ruling over a fascist state within the computer. It's also remarkably fallible for a supposedly godlike computer intelligence; insisting that video game expert Kevin Flynn "die within the games" when he's digitised into the ENCOM mainframe seems an especially daft move.
Agent Smith (The Matrix trilogy, 1999-)
The Matrix's antagonist starts out as just another Agent – a program designed to maintain order in the film's titular computer simulation. But when he's destroyed by Neo in the first film, he's "set free" – becoming a threat to machines and humans alike as he self-replicates and spreads throughout the Matrix.
Hugo Weaving's performance likewise starts out fairly understated, as a functionary menacing Keanu Reeves' Neo with the full weight of bureaucracy. By the third film, he's escalated to swivel-eyed, nihilistic lunacy in his final confrontation with Neo. And now he's shilling for General Electric. How the mighty are fallen.
Maschinenmensch (Metropolis, 1927)
When the saintly Maria becomes the figurehead of Metropolis' underclass, mad scientist Rotwang creates a robot replica to undermine her authority and spread chaos throughout the city. Which she achieves through the medium of sexy dancing. The robot itself seems to revel in the chaos it creates; it's no mere programmed functionary.
Actress Brigitte Helm's boggle-eyed performance as the robot Maria was, perhaps, partly down to the fact that director Fritz Lang insisted that she perform scenes in the iconic (and uncomfortable) robot costume, even though her face wouldn't be seen.
The Gunslinger (Westworld, 1973)
A precursor to The Terminator, the Gunslinger is a theme park attraction turned into a relentless killer when a computer virus causes it to malfunction. Yul Brynner donned his iconic outfit from The Magnificent Seven to play the murderous machine, whose eerie point-of-view shots were realised using computer processing to pixelate the image; the first digital effect in cinema history.
More mundane special effects were used for one chilling sequence in which acid is thrown in the android's face; Brynner wore make-up containing ground-up Alka Seltzer, which fizzed when he was splashed with water.