The power of movies is incredible. They can sweep us off onto a grand adventure, make us cry or fall in love, escort us to breathtaking places that don't exist -- or scare the living hell out of us. And nothing is quite as frightening as a movie monster. Whether they're using make-up, visual effects, or animatronics, films have brought the most terrifying creatures to life: Pennywise from It, and Freddy Kruger from A Nightmare on Elm Street. The list is endless.

Update October 8, 2023: This article has been updated with even more great monsters that showed up in non-horror films.

However, not all great monsters come from horror movies. They can be found in a fantasy or sci-fi epic or in something as innocuous as a child's animated film. We in the audience know these creatures are fake. And yet, their realness makes us scream and jump in our seats and can sometimes haunt us in the real world, forcing us to keep our lights on at night. Here are the most terrifying monsters outside the horror genre that continue to stalk our nightmares.

17 Oogie Boogie - The Nightmare Before Christmas (1993)

Oogie Boogie in The Nightmare Before Christmas
Buena Vista Pictures Distribution

On paper, The Nightmare Before Christmas shouldn't have worked. A stop-motion animated children's movie, full of scary monsters that kidnap Santa Claus? And is it a Halloween movie or Christmas movie? Yet, the Tim Burton produced film did work. Since its release in 1993, The Nightmare Before Christmas has become a holiday classic and is regarded as one of Disney's best-animated films.

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The movie features dozens of imaginative characters, like its iconic hero, Jack Skellington. But in a town packed with monsters, no one's as scary as the film's villain, Oogie Boogie. He's a walking, talking sack filled with crawling insects. He's so frightening that the character is kept locked up in an underground lair. Even Jack, the Pumpkin King, warns Boogie's three worshipers to "Leave that no good Oogie Boogie out of this!" And let's not forget: Oogie Boogie spends the entire movie trying to torture and murder Santa Claus.

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15 Sandworm - Dune (2021)

Timothee Chalamet and a sandworm in Dune
Warner Bros. Pictures

Worms aren't exactly frightening. But what about an enormous predator worm that roams the desert? That's the terrifying monster of the sci-fi film Dune. When you hear the rumblings in the distance announcing the sandworm's arrival, you know immediately that danger is on its way. Watching the characters run for their lives as the sandworm pursues them, seeing only bursts of sand rather than the actual creature, builds up the chase's suspense.

It's a jaw-dropping moment when the sandworm finally reveals itself, showing just how monstrous it really is. The scene where it dwarfs the characters' ship and swallows the vehicle whole is another memorable appearance. The sandworm will likely return in the sequel Dune: Part II, which is set to release in 2024.

14 The Sentinels - X-Men: Days of Future Past (2014)

Sentinels X-Men
20th Century Fox

The element of killer robots in any movie is always intriguing but also terrifying. In X-Men: Days of Future Past, robots known as Sentinels are tasked with hunting down mutants in the year 2023. The X-Men, led by Wolverine (Hugh Jackman), discover that villainous weapons designer Bolivar Trask created these mutant hunters back in 1973. So, Wolverine goes back in time to prevent the killer machines from being created.

Sentinels are technologically advanced and have the ability to replicate any mutant's abilities, allowing them to adapt to their targets and make them unstoppable killing machines. Seeing these terrifying machines lay waste to some of the most powerful mutants like Magneto, Storm, and Colossus immediately shows how terrifying they are and puts the viewer on the edge of their seat to see if they can be stopped.

13 King Ghidorah - Godzilla: King of the Monsters (2019)

Godzilla vs King Ghidorah
Sony Pictures

Godzilla: King of the Monsters pits Godzilla against one of his fiercest and most legendary foes, King Ghidorah. An alien from another world, King Ghidorah is an apex predator that rivals Godzilla. It's a massive dragon-like creature with three heads, each with its own personality. It can also shoot electrical currents and beams of energy. King Ghidorah's only goal is to become Earth's most dominant monster, and has no regard for the destruction that's left in its wake, making it one of the most terrifying monsters in film.

12 Terror Dogs - Ghostbusters Franchise

Vinz Clortho-1 (1)
Sony Pictures Releasing

Ghostbusters is a classic 80s movie whose success has spawned a franchise that includes an upcoming sequel. The original film is a comedic joyride, and most of its ghosts are quirky and harmless, such as the lovable Slimer. That is until the terror dogs show up. They're demons from hell, horned beasts with sharp teeth and red, glowing eyes.

Their appearance is frightening, but it's their focused targeting that makes these hellhounds so scary. Once the terror dogs target you, it's over. They keep coming after you, and only you, until they possess your mind and body. Watching a terror dog chase the helpless Rick Moranis through Manhattan's streets or appear in Sigourney Weaver's fridge roaring viciously is something out of a horror film. The beasts returned in the latest sequel Ghostbusters: Afterlife, proving that they're just as frightening now as they were in the 80s.

11 Dementors - Harry Potter Franchise

Harry Potter - Dudley being Killed by a dementor
Warner Bros. Pictures

Dementors are the most frightening creatures in the Harry Potter franchise. Based on J.K. Rowling's experience with depression, Dementors are hooded, floating dark creatures that suck the happiness, and eventually the soul, from your body. They're also the infamous guards of the wizard prison known as Azkaban. Every time they come on screen, the atmosphere grows cold and tense, and the characters' faces fill with fear. The scene where the Dementor first appears and attacks Harry and his cousin Dudley makes for one of the scariest moments in the series.

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10 The Wheelers - Return to Oz (1985)

Dorothy and the Tin Man talk with a Wheeler
Buena Vista Distribution

In what could be called the sequel to the beloved classic known as The Wizard of Oz, Return to Oz tells the story of Dorothy Gale's return to the land of Oz after she is put in a sanatorium due to her delusions of Oz. Once she arrives back in Oz, she is chased by the Wheelers, a group of men with wheels for hands and feet. They are the psychotic henchmen of the evil Princess Mombi, who wants Dorothy's head for her own collection.

The Wheelers have an evil laugh and awfully scary look, which is why Dorothy freaks out when they threaten to tear her apart. Despite this film being rated PG, these evil henchmen certainly are anything but PG. Think of them as evil security guards. No fun and only fright. If you don't follow the rules of their land or if you come across their path, they will torment you.

9 Rancor - Star Wars Franchise

Grogu befriending a Rancor
Disney Platform Distribution

The Star Wars franchise is packed with alien species. However, none of them are as scary as the dreaded Rancor. It made its debut in The Return of the Jedi as the monster in Jabba the Hutt's fortress. The film's hero, Luke Skywalker, is sent plummeting to an underground chamber, where a massive door opens to reveal Jabba's pet. At the time, the audience didn't know what danger lurked behind this door -- and when it was revealed, it didn't disappoint.

The Rancor is a huge monster with long arms and a vicious disposition. Even Luke, a powerful Jedi who had been nothing but calm so far in the movie, was rattled by its presence. Every time its name was mentioned in Disney+'s The Book of Boba Fett, characters reacted to it with fear. The Rancor eventually made an appearance in the show, terrifying audiences all over again from their couches.

8 The Kraken - Pirates of the Caribbean: Dead Man's Chest (2006)

Pirates of the Caribbean Kraken
Buena Vista Pictures

This is the most devilish creature in the Seven Seas. As Davy Jones's pet in Pirates of the Caribbean: Dead Man’s Chest, the Kraken wreaks havoc on every ship that stands in the way of the Flying Dutchman. Its long tentacles and swift power make it nearly unbeatable. Sailors never see it coming, and by the time that they do, it is too late. The only crew that puts up a great fight against it is the crew of the Black Pearl.

However, as the crew escapes without Jack Sparrow (Johnny Depp), the beast returns and sends Sparrow to Davy Jones' Locker. But before it does that, it lets him know how angry it is by roaring at Jack and blowing its mucus at him. The Kraken is an elemental force, one that puts the heroes in an unstoppable situation that makes it difficult to win. The only person that can vanquish it is Davy Jones himself.

7 The Balrog - The Lord of the Rings: The Fellowship of the Ring (2001)

The Balrog of Morgoth in The Lord of the Rings: The Fellowship of the Ring
New Line Cinema

The Lord of the Rings: The Fellowship of the Ring features lots of iconic moments. But its most famous scene has to be the appearance of the Balrog, a massive, fiery beast that prowls the Mines of Moria. Gandalf the Grey, the film's wizard and most powerful character, tries desperately to avoid the mines, choosing instead to scale a mountain during a blizzard, because he's terrified of the Balrog. And once we see it, we immediately understand why. Its insidious presence makes for one of the most epic and frightening moments of the entire series.

6 The Seven Deadly Sins - Shazam! (2019)

The Seven Deadly Sins in Shazam
New Lie Pictures/Warner Bros.

Shazam! was marketed as a funny family friend superhero romp with the fun premise of a kid becoming a superhero. It seemed incredibly lighthearted. Yet despite it being helmed by horror filmmaker David F. Sandberg (Annabelle Comes Home), nobody could have expected it to be as scary as it was, particularly with the film's main villains being the Seven Deadly Sins.

The Seven Deadly Sins were a perfect mixture of Shazam! comic book lore, Golden Age mixture of monsters and superheroes, B movie pictures, stop motion monsters, and horror movie aesthetics. These creatures were brutal, killing an entire boardroom full of people in a gruesome manner and even threatening kids. It's actually a genius move: put your superhero up against traditional monsters out of a horror film to make the hero seem more heroic and kid-friendly. Yet, if not for the hero, these characters could have been the main monsters in their own terrifying horror film.

5 Flying Monkeys - The Wizard of Oz (1939)

Wicked Witch Hourglass

It is fair to say that the Flying Monkeys from The Wizard of Oz are the scariest primates in all of cinema. Under the leadership of the Wicked Witch of the West, they attack Dorothy Gale and her friends in the dark forest. After literally tearing the Scarecrow to shreds, they pick up Dorothy and fly her to the witch's castle, where she is imprisoned until her friends return to save her.

With blue faces and red lips, the monkeys have a striking look. They put fear into the citizens of Oz and the audiences as well. It is safe to say these creatures gave many kids nightmares for years to come.

4 Chernabog - Fantasia (1940)

The devil in Fantasia
Disney

When people think of Walt Disney's animated classic Fantasia, they usually recall one of two scenes. The first is The Sorcerer's Apprentice, which shows Disney's flagship character, Mickey Mouse, donning the iconic sorcerer's hat. The other scene is Night on Bald Mountain, which features the demonic, Satan-like character Chernabog. Disney has created many great villains over the years, but Chernabog might just be their best. Unlike other Disney villains, he has no motive or origin story. He is simply evil incarnate. Chernabog's introduction -- opening his great wings to reveal himself, while Mussorgsky's Night on Bald Mountain booms sinisterly in the background -- is both masterful and terrifying.

The demon spends most of his time in the shadows. But the audience does catch a glimpse of his malevolent smile as he carelessly throws souls into the flames below. Although Chernabog's appearance is brief, he's become legendary in Disney lore and has been haunting audiences since 1940. A live adaptation of Night on Bald Mountain was reportedly in the works, though it's unclear if the project is still in development.

3 Tyrannosaurus Rex - Jurassic Park Franchise

Jurassic Park
Universal Pictures

Few things are as scary as the Tyrannosaurus Rex from the Jurassic Park franchise. From the moment the audience sets foot in Jurassic Park, we're eager to see the genetically altered reincarnation of the extinct creature. The film's director, Steven Spielberg, teases us with its appearance, showing us the dinosaur's meal, a living goat, but not the T-Rex itself. Then suddenly, the goat is gone, the power in the park is out, and all hell breaks loose, along with the famous dinosaur.

The T-Rex stepping out of its confines and unleashing a spine-tingling roar, unveiling itself for the first time, is as terrifying as it is iconic. It wreaks havoc for most of the movie, chasing and killing the people it encounters. The T-Rex's thundering footsteps, coupled with those famous shots of rippling water, build up the movie's suspense and horror, making our hearts race before the dinosaur even comes on screen. The T-Rex isn't just one of the most dangerous dinosaurs in the series; it's one of the most frightening monsters outside the horror genre.

2 Judge Doom - Who Framed Roger Rabbit? (1988)

Judge Doom from Who Framed Roger Rabbit
Buena Vista Pictures Distribution

Can a toon be a monster? Well, this one certainly is. Judge Doom was already a terrifying antagonist in Who Framed Roger Rabbit? before the audience found out his twisted secret. Brought to life by Christopher Lloyd, Doom was a cold, calculating villain who created a formula that allowed him to kill Toons. This already made him extremely dangerous.

Yet the film's climax reveals he is a toon wearing a human costume. The only parts of Doom's true form that audiences get to see are his evil eyes and his high-pitched voice. The image of Doom popping up after being flattened by a steamroller gave kids nightmares for years. This is a character so evil that not only did he kill Eddie Valiant's (Bob Hoskins) brother, but in the original script, he was also going to be revealed as the killer of Bambi's mom. Judge Doom is a monster that could go toe to toe with any horror movie monster any day.

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