2016's Split had people talking for being a sequel to Unbreakable all along, even though it wasn't promoted as such. And while that movie is the most obvious example of a secret sequel, other movies have kept hidden from audiences that they're direct sequels or prequels to other movies until their final minutes.

RELATED: M. Night Shyamalan's Films Ranked From Absolute Worst To Best (Including Old)

These secret sequels usually tell an engaging standalone story, and if viewers watch closely, they'll usually find hints that give the reveal away early on. And there are other times when studios have fooled audiences into thinking they're seeing a remake of an iconic movie, only for the reveal that it's a prequel to be as shocking as possible.

The Thing (2011)

Rent On Apple TV

Kate Lloyd watching Carter-Thing burn in the snowcat in The Thing 2011

2011's The Thing was sold to audiences as a remake, and though it had negative reviews from critics and wasn't received all that well from moviegoers, it had one of the biggest surprises that nobody saw coming. The film isn't actually a remake, but a prequel to the 1982 horror classic.

The original movie begins with a dog being chased by a helicopter to an American research station in Antarctica. The passenger of the helicopter tries to warn the Americans of the dog, but they don't understand him and the helicopter blows up. At the end of the 2011 movie, while audiences are still under the impression that the film's a remake, the two only surviving characters realize that their dog is now the Thing, and as it runs away, they pursue it by helicopter.

Split (2016)

Stream On DirecTV

David Dunn sits in a diner in Split

Split is a gripping thriller about a man with multiple personality disorder who kidnaps women, and for the whole of the movie, that's all it is. But the mid-credits scene reveals that it's actually a sequel to 2000's Unbreakable, and it's setting up a cinematic universe.

RELATED: 7 Best Unbreakable Franchise Characters, Ranked

Unlike many of the other movies that are secret sequels to classic films, Split didn't even try to use the final reveal to market the film. That's a testament to how great of a standalone movie it is, and if the scene in the diner at the end wasn't ever shot, it wouldn't have hindered the film's quality. However, there was one ingenious hint at the shared universe in Split's poster, as Kevin stands behind shattered glass, and Mr. Glass is the villain in Unbreakable.

21 Jump Street (2012)

Stream On DirecTV

Johnny Depp in 21 Jump Street

Though the original 21 Jump Street was a TV series, the 2012 movie still secretly hides that it's a continuation of the show. 21 Jump Street is another movie that gave audiences the impression it was a complete remake, especially considering that it completely changed the tone of the original.

But in the final act of the movie when Greg and Schmidt are close to cracking the case, Tom and Doug, the two main characters from the series, pull off their disguises and explain that they have been working on the case for five years. They even bond with Greg and Schmidt about working for Jump Street too, and the cameos are why it's still better than 22 Jump Street.

Prometheus (2012)

Stream On Amazon Prime

A baby xenomorph is born in Prometheus

There were hints throughout the movie that Prometheus was in the same universe as the Alien series, such as the pilot's seat and the spacecraft, but nobody had any idea that it was going to be such a direct prequel. Though prequels can often be damaging to movie franchises and answer questions nobody was askingPrometheus does a great job at expanding the world while still leaving a lot of the mystery intact.

As the movie was marketed as a sci-fi movie about scientists trying to find life's creators, audiences thought they were going to be told the meaning of life when sitting down to watch it. So it would have come as a huge surprise when the reveal of the xenomorph came at the very end of Prometheus.

10 Cloverfield Lane (2016)

Rent On Vudu

Marlena in Hazmat Suit in 10 Cloverfield Lane

While there's a very big hint in the title that 10 Cloverfield Lane is a sequel to Cloverfield, there was a huge mystery surrounding the movie when it was first released. It was marketed as an isolated thriller movie about a psychotic kidnapper and his bunker, but the final 15 minutes revealed that his ramblings about an apocalyptic disaster were all true.

In the closing minutes of the movie, Michelle makes her way out of the bunker only to find a swarm of alien creatures that has taken over Earth. And though it expertly ties the movie into the franchise, there are others who think the last few minutes ruin 10 Cloverfield Lane.

Star Trek (2009)

Rent On Vudu

The two Spocks meet in Star Trek 2009

There's no other movie more marketed as a reboot only to end up being a sequel to another movie than 2009's Star Trek. The J.J. Abrams-directed action-adventure take on the decades-old franchise was thought to be a reboot of the very original series, especially as a whole new cast played younger versions of the same characters.

RELATED: 10 Best Shows Like Star Trek: Picard

However, mid-way through the movie, Spock runs into the older version of himself, who is played by Leonard Nimoy, the very actor who played the Vulcan in all those movies and episodes of the show. That makes the 2009 film a direct sequel to 1991's Star Trek VI: The Undiscovered Country, the last movie that Nimoy starred in.

Enemy Of The State (1998)

Stream On Tubi TV

Split image Gene Hackman as Harry in The Conversation and Brill in Enemy of the State

1998's Enemy of the State, one of Tony Scott's best movies, is about Edward (Gene Hackman), an NSA agent who attempts to cover up an assassination attempt on a congressman. There are a lot of similarities between the film and 1974's The Conversation, another movie about spying and surveillance starring Hackman as Harry. And it's almost certain that Edward and Harry are the same person.

While it's more of a theory than anything and it's inconclusive as to whether Enemy of the State really is a sequel to The Conversation, there are way too many clues for it not to be. Edward's NSA file is a photo of Harry from The Conversation, Edward dresses like Harry and has the exact same lifestyle, and there's even a point in which somebody calls Edward "Harry."

Catwoman (2004)

Stream On HBO Max

Patience looks at a photo of 1992's Catwoman in Catwoman

On the face of it, Catwoman is a completely standalone movie about one of the most iconic antiheroes ever, but it's actually a sequel. Even though fans don't want to hear it given that it's one of the most critically panned and most hated superhero movies ever, the 2004 movie is technically part of Tim Burton's Batman universe.

In the movie, Patience can be found looking at photos of previous catwomen, including Selina Kyle from 1992's Batman Returns. Though it's more of an Easter egg than anything, it still puts Catwoman in the same universe as Burton's Batman Returns and makes it somewhat of a sequel to the gothic 1992 movie.

NEXT: The Batman - 8 Things The Movie Got Right About Selina Kyle