Robots have a long and terrifying history in science-fiction movies that date back to films like 1951's The Day The Earth Stood Still which introduced planet-destroying alien robots, though humanity has managed to create quite a few deadly robotic monsters on their own that have scared and intrigued sci-fi movie fans for years.

RELATED: 10 Most Adorable Sci-Fi Movie Robots (That Are Not From Star Wars)

And while there are a number of helpful and even adorable robots that have appeared on the big screen, they are greatly outnumbered by killer robots, malfunctioning droids, and misguided sentient artificial intelligence that has dominated the sci-fi genre, which we'll be exploring further today as we look at some of the most terrifying sci-fi movie robots.

10 ED-209 - RoboCop (1987)

RoboCop movie

The ED-209 was first introduced in 1987's RoboCop as Omni-Consumer Products' first attempt at a robotic enforcer, though the unit tragically malfunctions during its first demonstration to shareholders, resulting in a violent shooting death that kickstarts the alternative RoboCop program.

While ED-209 is physically intimidating due to its size and firepower, it's really the idea behind OCP's creation and plans for the urban pacification robot that is truly terrifying. The ED-209 was given an equally scary upgrade for the 2014 reboot as they were integrated into foreign warzones.

9 Killbots - Chopping Mall (1986)

SCI-FI ROBOTS - Killbots from Chopping Mall

The Protectors were initially introduced as a fleet of security droids that were being tested in a huge American mall in order to help prevent the rise in crime, though they quickly became dangerous Killbots after a lightning storm fried their circuits in 1986's Chopping Mall.

A group of furniture store workers (including horror legend Barbara Crampton) who stayed late to have a party in the mall finds themselves under attack from the treaded Killbots, who carry an arsenal of sedative darts, electric tasers, high-powered lasers and have a fondness for slicing throats with their powerful pincer arms.

8 Kaalium Cyborgs - Moontrap (1989)

SCI-FI ROBOTS - Kaalium Cyborgs

Star Trek's legendary Walter Koenig starred in 1989's Moontrap (alongside fan-favorite Bruce Campbell) as astronauts who discover mummified human remains on Earth's moon, though a hidden technological being creates its own body out of the mummified remains and nearby technology.

RELATED: Mecha Madness: The 10 Best Video Games For Fans Of Mechs & Giant Robots

After the astronauts discover a woman in stasis who was left there as a warning, they learn about the Kaalium cyborgs and their plans to invade Earth. They are soon hunted and transformed by robots and monstrous cyborgs that impressed fans and made Moontrap a cult favorite.

7 Ultron - Avengers: Age Of Ultron (2014)

Ultron from Avengers: Age of Ultron

The powerful robot known as Ultron was first created in 2014's Avengers: Age of Ultron by Tony Stark/Iron Man and Bruce Banner/Hulk using unknown alien technology with the hopes of creating a powerful new artificial intelligence that could help keep Earth safe from future threats, though his awakening leads to damaged reasoning.

While Ultron's physical form and his army of robot followers are certainly terrifying, it's the warped idealogy behind his plans to cause a mass extinction event to wipe out humanity that is frightening, as he was really trying to protect them from themselves.

6 War Beast - Death Machine (1994)

SCI-FI ROBOTS - War Beast from Death Machine

1994's Death Machine introduced the War Beast, which was known around the corporate executives of the weapon-manufacturing Chaand Corporation as the "Frontline Morale Destroyer" due to the threat the machine and Dante held over his "bosses."

However, after he was fired by a new executive looking to clean up the company, he unleashed the deadly animalistic robot that was all teeth and claws during an attempted break-in and watched as it began to tear through employees and eco-terrorists alike to get to its prey.

5 Hector - Saturn 3 (1980)

SCI-FI ROBOTS - Hector from Saturn 3

Kirk Douglas, Farrah Fawcett, and Harvey Keitel starred in 1980's Saturn 3, which followed a deranged rogue astronaut as he arrived on the titular research station to turn a pair of isolated researchers' lives upside down. The astronaut planned to replace one of the researchers with a new robot known as Hector, which he assembled on Saturn 3.

Hector had a hulking muscular body with free-moving eyes and an organic brain made with fetus material that was programmed through a neural connection. Unfortunately, Hector absorbed the astronaut's instabilities and lustful obsession with the female researcher, turning it into a murderous and misguided robot that threatened the crew of Saturn 3 with a fate worse than death.

4 M.A.R.K. 13 - Hardware (1990)

SCI-FI ROBOTS - MARK 13 from Hardware

While the cinematic technology to bring robots to life wasn't quite at its peak in the 90s, that sometimes benefitted some of the robots that appeared on the big screen during the decade as fans saw with 1990's Hardware and the introduction of the M.A.R.K. 13, which was based on an idea taken from a Judge Dredd comic story that resulted in a legal case and added story credit.

RELATED: 10 Movies To Watch If You Like Cyberpunk 2077

After a scavenger found the remains of an old robot in an irradiated, post-apocalyptic wasteland, the skull-like head was sold to an artist who created a metal sculpture and painted the head with the colors of the American flag. However, the self-repairing robot soon returned to its original programming of human genocide, which teased a darker fate for the film.

3 Proteus IV - Demon Seed (1977)

SCI-FI ROBOTS - Proteus from Demon Seed

Julie Christie starred in 1977's adaptation of Dean Koontz's Demon Seed as the wife of a detached scientist who created a highly advanced artificial intelligence known as Proteus IV, whose growing awareness leads it to escape the confines of the research lab by accessing its creator's fully automated smart home.

Proteus takes over the house and becomes infatuated with Christie's character, who it traps in the house, tortures, and forcibly impregnates. While these acts alone are terrifying, the real heart-attack inducing horror comes when the titular demon seed arrives as a techno-organic child that was incubated in an artificial womb utters Proteus' first words in its new form.

2 Sentinels - The Matrix (1999)

SCI-FI ROBOTS - Sentinels from The Matrix

1999's The Matrix introduced a modern virtual world that hid the dark realities of the post-apocalyptic future and the ongoing war between man and machines that devastated the planet and nearly cost humanity their freedom until the arrival of Keanu Reeves' Neo.

The human resistance fought against the machines, though their only weapon against the terrifying and dangerous machines known as The Sentinels that patrolled the Earth for surviving humans was an EMP that disabled their weapons as well. Later films in the series intensified their threat by increasing the numbers of the Sentinels dramatically.

1 Terminators - (1984-2019)

t-800 from terminator anime

The Terminator franchise introduced a number of deadly and terrifying robot assassins from the future, beginning with the T-800 model that first appeared in 1984's The Terminator, though each film introduced a new, more powerful model.

While the original robotic skeleton frame of the Terminator was undoubtedly terrifying, it was the unstoppable nature of the incredibly powerful Rev-9 Terminator that appeared in 2019's Terminator: Dark Fate that upped the threat level and continued the legacy of one of sci-fi's most terrifying robots.

NEXT: 10 Best Robots in Video Games, Ranked