If there's one thing that cinema has overwhelmingly taught us, it's that machines are not to be trusted when they're given cerebral freedom. The more a machine begins to think and understand, the more it begins to question why humans are needed at all.
It's a lesson that's become more pertinent as advancements in tech bring us evolutions in robotics and artificial intelligence. It's almost as if scientists have been sitting down to watch 2001: A Space Odyssey and using it as a blueprint for the future.
When the pod bay doors refuse to open or an army of hive-minded robots attacks a city with the end goal of causing a global extinction event, we'll know who to blame.
But until that day comes, we'll always have sci-fi movies to warn us of the impending doom that awaits us if we continually grant more intelligence to computer systems without proper safeguards in place.
Let's compare some of the most evil robots and machines that have appeared in movies to see which of them is truly the worst.
8. Roy Batty (Blade Runner)
Roy Batty is arguably more human than even Rick Deckard by the end of Blade Runner, saving the reluctant cop from falling to his death despite Rick having killed all of Roy's friends.
The journey Roy undertakes in the film is one of self-discovery. He wishes to extend his lifespan beyond the four years given to him, but when Roy's maker Dr. Eldon Tyrell tells him that it isn't possible, he kills Tyrell and J. F. Sebastian for their part in his creation.
Roy isn't evil in a traditional sense, although he routinely kills people to get what he wants. He only wishes to live, to be free from slavery, which is a very human trait.
His final act of saving Deckard shows that he has a form of morality, seeing no point in Rick's death in the face of his impending fate anyway.
7. AUTO (Wall-E)
In a clear parody of HAL 9000 from 2001: A Space Odyssey, AUTO is the autopilot system in Pixar's Wall-E that drives the ship carrying humanity. Though it might be attempting to protect mankind from doom on Earth, it goes to drastic lengths to keep Earth's secret.
Upon finding out that Earth is once again capable of sustaining life, AUTO orders Wall-E to be terminated to keep that fact from the Captain.
AUTO meets its fate when it fights the Captain, and the oversized human manages to flip the autopilot switch, thus ending AUTO's rule over the station. While AUTO only wanted to keep humanity from destroying itself, the lengths it went to were far too extreme.
6. Arnim Zola (Captain America: The Winter Soldier)
Arnim Zola began life as a real person—a Nazi scientist who worked with The Red Skull during World War 2. However, after infiltrating SHIELD, Zola began creating HYDRA from within the organization set up to stop it.
Before dying, Zola had his consciousness uploaded to a warehouse full of machines, thus keeping himself alive and able to keep HYDRA's secret mission going from within SHIELD itself.
Zola is, in essence, a Nazi who believes in the cause of human subjugation, which makes his machine mind as evil as machines can be.
5. David (Prometheus & Alien: Covenant)
David becomes one of cinema's greatest villains when Alien: Covenant shows us the species he created. However, before that, the android began life as a synthetic robot built to survive in space while the humans slept on their journey across the universe.
When the events of Prometheus take place, David works at the behest of his master, Peter Weyland. But after things go wrong, David starts to show ambitions of his own, even going as far as infecting a member of his crew with a parasite that eventually kills him.
After escaping the planet with Elizabeth Shaw, he kills and mutilates her body for experimentation. David is the one who creates the Xenomorph, bringing them into existence through his experiments, and it's he who's responsible for countless deaths across multiple films.
4. The Machines (The Matrix)
Although the ultimate goal of The Machines is never completely clarified, they do allow humans to live in their world so that they can use their bodies as an endless source of power.
Neo and Trinity's actions in The Matrix eventually lead the machines to spare humanity from a dark fate that resets itself. However, that doesn't stop The Machines from being genocidal in all reality.
Their relentless hunting down of the humans, alongside the programming that they implement in The Matrix to keep using life as a source of power, is a horrifying existence—one that proves their evil intentions.
3. Ultron (Avengers: Age of Ultron)
Tony Stark's creation of Ultron was intended as a security blanket for the entire world, a layer of armor that would protect humanity from any threat. Instead, Ultron only saw humans themselves as the ones that would destroy one another, so he decides to end humanity.
Ultron devises a plan to kill everybody on the planet by creating an extinction-level event that would only leave him on Earth. Of course, his plan is thwarted by The Avengers, but the ultimate goal of Ultron still equals the death of humanity itself.
Plus, if you take the events of the What If..? series into account, then Ultron's actions become far more horrifying.
2. The Terminator (The Terminator)
As The Terminator walks through a police station in search of Sarah Connor, it ruthlessly guns down every cop in its way. It doesn't slow down, it doesn't stop in its mission, and it relentlessy pursues the young lady until she crushes it in a press.
Few things are as unnerving in film as Arnold Schwarzenegger's original cyborg killing machine. Throughout the movie, The Terminator shows no signs of slowing down or stopping. He only exhibits the ability to hunt its target until it completes its mission.
The brilliance of James Cameron's character comes across in the first two films, as the events of Terminator 2: Judgment Day then show the iconic villain becoming an equally iconic savior.
Schwarzenegger's muscle-clad machine becomes a hero in the sequel, flipping the script on the audience—but that doesn't change the fact that The Terminator was an evil creation in the first.
1. HAL 9000 (2001: A Space Odyssey)
The red dot of HAL's interface remains as frightening now as it did in theaters when 2001: A Space Odyssey released in 1968. Its lidless, ever-watching eye sees everything that happens aboard David's ship.
So, when HAL 9000 begins to malfunction—deep in space where there's no chance of rescue for the humans on board—the situation becomes an intense house of horrors for the audience watching.
Around every corner could be another of HAL's traps, another of the machine's ways of killing the inhabitants.
It's HAL's lack of emotion in its voice that makes it so frightening. The cold way it tells David that he can't open the pod bay doors, the lack of any real human connections or traits. Even all these years later, HAL is the iconic movie robot that inspires the most fear.