Prior to “Iron Man” kickstarting the Marvel Cinematic Universe, combining apparently unconnected movies was uncommon, even if they were from the same creator. The Universal Monsters did have their own niche in horror films, but that was essentially it. Since 2008, there have been numerous attempts to mimic Marvel’s formula, yet most of these cinematic universe efforts have flopped. Nonetheless, there are still other franchises and films that are intertwined — and even exist in the same universe — often without people noticing.

This typically begins as an Easter egg, like the Xenomorph skull that appeared in the closing scenes of 1990’s “Predator 2.” This small detail eventually led to comic book crossovers and a feature film, “Alien vs Predator,” in 2004. Yet, these lesser-known connections often remain unnoticed, either because they’re overlooked entirely or audiences don’t fully realize their significance in the storyline. 

So, what makes a universe connected? It’s got to be more than just a joke, which is why we’re excluding crossovers in pure parody films like “National Lampoon’s Loaded Weapon 1,” featuring cameos from “Star Trek’s” Scotty and Bruce Willis’s John McClane. We’ll be focusing on crossovers that have received approval from their creators, writers, directors, and actors, even if studio rights complicate things. Here are films you likely didn’t realize were set in the same shared universe.

It should come as no surprise that two movies penned by the same screenwriter might exist in the same shared universe, even if one movie is an original work and the other based on a classic sci-fi story. This is the case with “Blade Runner” and “Soldier” — which is why so many people miss this one.

The 1982 sci-fi thriller “Blade Runner” is based on Philip K. Dick’s short story, “Do Androids Dream of Electric Sheep?” and has long been considered one of the best sci-fi movies ever made. It’s set in a dystopian future where androids, known as replicants, exist and can blend in with society. A replicant named Roy Batty (Rutger Hauer) gives a moving speech at the climax of the film where he references off-world locations — specifically, Tannhäuser Gate and the Shoulder of Orion.

Fast forward to 1998 and Kurt Russell’s sci-fi action movie “Soldier,” an original story from screenwriter David Webb Peoples — the same man who helped craft the script to “Blade Runner.” In “Soldier,” Russell’s character, Sgt. Todd 3465, has been raised since birth by the military. We learn that he, like Batty, took part in battles at Tannhäuser Gate and the Shoulder of Orion. Meanwhile, one of the iconic “spinner” flying cars from “Blade Runner” appears in the background of one scene — cementing “Soldier” as a part of that film’s universe.

Written and directed by auteur filmmaker Quentin Tarantino, “Jackie Brown” was the first movie to follow the breakout success of “Pulp Fiction.” And somewhat ironically, it’s also the only movie in the director’s filmography to be based on someone else’s work. That work was the book “Rum Punch” by novelist Elmore Leonard, and thanks to Tarantino’s love of blaxploitation, it stars ’70s icon Pam Grier in the title role. A clever crime caper comedy, it’s one of Tarantino’s best, even if it isn’t one of his biggest hits.

“Out of Sight” was released a year after “Jackie Brown” and was directed by Steven Soderbergh. It stars George Clooney as a bank robber being hunted by a female bounty hunter (Jennifer Lopez). It wasn’t a huge hit either but did earn itself a TV spin-off, “Karen Sisco,” starring Carla Gugino. But because “Out of Sight” wasn’t as widely seen or fondly remembered as “Jackie Brown,” many audiences forget that two characters from Tarantino’s movie had small roles: Samuel L. Jackson and Michael Keaton, who appear in cameos. And it makes sense, because “Out of Sight” was also based on a novel by Elmore Leonard.

Interesting, “Karen Sisco” had its own crossover with another Elmore Leonard TV show: In 2012, Gugino reprised the title role in an episode of FX’s “Justified.”

When considering shared movie universes (official or unofficial), one usually thinks of films that have a lot in common, and that’s true for most of the entries on this list. “Blade Runner” and “Soldier” are both sci-fi movies set in the future; “Jackie Brown” and “Out of Sight” are both crime comedies. But you couldn’t ask for two more wildly different movies than “Spy Kids” and “Machete,” and yet — believe it or not — they exist in the same universe, and it’s definitely not a fan theory.

“Spy Kids” is a 2001 action-comedy meant for kids, about two young siblings who discover to their amazement that their parents (Carla Gugino and Antonio Banderas) are global super-spies. But when their folks are taken captive by a diabolical criminal mastermind, the two kids must become spies themselves to help save the day. You might wonder what the heck this has to do with a brutally violent, R-rated splatterfest like “Machete,” but when you realize that both were directed by Robert Rodriguez, you start to see where this is going. 

Released in 2010, “Machete” stars Danny Trejo as a former Mexican Federale named Machete who goes on a bloody mission of vengeance. But surprisingly, Machete’s first on-screen appearance was in “Spy Kids” as the kids’ uncle, who helps them on their own dangerous mission. Oh, and Machete once turned up in a Snickers commercial that featured the Brady Bunch, so we can lump that sitcom into this universe too. Maybe Trejo isn’t wrong when he says Machete is as culturally relevant as Superman.

Filmmakers rarely consider the canonical implications of a cameo, because it’s usually just a joke. And that was probably what happened in 1988 when it occurred in the Eddie Murphy comedy, “Coming to America.” The film saw Murphy playing African prince Akeem Joffer, who takes a trip to America to find a suitable bride.

In America, Joffer tries passing himself off as a lowly commoner to impress a woman named Lisa (Shari Headley). Dismayed when his assistant Semmi (Arsenio Hall) furnishes his apartment lavishly, Joffer donates all their money to two homeless men. At first glance, it might seem like a fun little gag, but the two homeless men are Mortimer Duke and his brother Randolph, played by Don Ameche and Ralph Bellamy — the two wealthy antagonists of Murphy’s earlier movie, “Trading Places” — who wind up in poverty at the end of that film. The two return in “Coming 2 America,” seen in paintings on an office wall, making this more than a mere one-off gag.

Some may dismiss this one because Eddie Murphy plays the hero in both films, nixing the notion that they could be in the same universe. But remember that Murphy already plays multiple roles in “Coming to America” — as Joffer, a barbershop owner, and of course Randy Watson, lead singer of Sexual Chocolate, one of the best fictional music groups in TV and movie history. And don’t take our word for it: “Coming 2 America” director Craig Brewer insists there could still be a crossover movie.

You’d probably wonder how a movie set in the Wild West following the American Civil War and another about a crime-busting private detective in contemporary 1970s New York City could be related. Throw in the fact that the two films share no common links — not the same writer, director, or actor — and you are likely asking yourself what the heck we’re talking about when we say that “Shaft” and “Django Unchained” exist in the same universe.

But remember Quentin Tarantino’s love of blaxploitation? Well, the man just couldn’t resist linking his work to one of the most famous blaxploitation movies ever made. In his 2012 film “Django Unchained,” we meet the titular gunslinger, an escaped slave played by Jamie Foxx, who goes on a rampage to free his wife from her oppressors. That wife is Broomhilda, played by Kerry Washington, and while the film doesn’t make any mention of the connection for obvious reasons (“Shaft” takes place 100 years later), it becomes obvious when you learn that her full name is Broomhilda von Shaft. 

That was revealed later by Tarantino himself, who declared that the character is indeed intended to be an ancestor of Richard Roundtree’s inscrutable John Shaft.  Adding an extra layer of irony, of course, is that “Django” co-star Samuel L. Jackson also played John Shaft (the original’s nephew) in two 21st century sequels.

A cult classic about the perils of toxic masculinity, 2000’s “American Psycho” is a controversial adaptation of a banned book by Bret Easton Ellis. It’s since become a seminal turn-of-the-century classic, while helping to make star Christian Bale a sought-after name in Hollywood. Bale plays Patrick Bateman, a smarmy banker on Wall Street obsessed with wealth, power, and self-image. Beyond his greedy exploits by day, however, Bateman also moonlights as a sociopathic serial killer.

By contrast, “Rules of Attraction” is a dark comedy starring James Van Der Beek of “Dawson’s Creek” fame as a drug dealer caught up in a bizarre love triangle. But when you learn that Van Der Beek’s character is named Sean Bateman, you begin to see the connection: The two lead characters are brothers, as “Rules of Attraction” is also based on a book by Bret Easton Ellis. In fact, there’s even a deleted scene in “Rules” where Sean Bateman calls his older brother Patrick, looking for money — although Patrick is played here by Casper Van Dien and not Bale.

Interestingly, another Ellis book, “Less Than Zero,” also takes place in the same fictional universe. But the 1987 movie version, starring Andrew McCarthy and Robert Downey Jr., omits the connections from the book.

Movie adaptations of classic comic books boomed in the 1990s, likely spurred by the incredible success of Tim Burton’s 1989 smash hit “Batman.” And it wasn’t just superheroes, with titles like Harvey Comics’ “Richie Rich” turned into feature-length adventures too. Another Harvey character, Casper the Friendly Ghost, got his own big screen outing in 1995. Mostly forgotten today, it stars Christina Ricci as Kat, a young, lonely teenage girl who befriends the ghost of a boy who died years earlier. That boy is Casper, whose specter remains — along with that of his two uncles — in the stately manor owned by a greedy socialite, Catherine Crittenden (Cathy Moriarty), who wants them gone.

While “Casper” never became a classic, the film was a big hit in theaters, earning nearly $300 million at the box office. But what many probably don’t remember is the fact that one sequence firmly establishes it as taking place in the same world as another classic ghost-centered comedy. The scene in question comes when Cathy hires a series of paranormal experts to rid her home of the ghosts, with each of them failing miserably. One of those experts is Ray Stantz, Ghostbuster extraordinaire, played of course by Dan Aykroyd (and with a mustache this time). So is Casper really part of “Ghostbusters” canon? We think so. 

Few fans would ever think to connect an over-the-top sci-fi action schlockfest with the gritty reboot of one of the horror genre’s most famous franchises. But look beneath the surface and you’ll find some evidence that they are not so far removed from one another as you might expect. That’s because “Transformers” director — and infamously bombastic filmmaker — Michael Bay is actually a producer on the 2009 remake of “Friday the 13th.” 

That reboot, starring Jared Padalecki, Danielle Panabaker, Aaron Yoo, and Amanda Righetti, retells the iconic story of Jason Voorhees, a mysterious hockey mask-wearing psycho who murders his victims with a machete. But how is that connected to a sprawling franchise about giant robots from outer space fighting a centuries-long war on Earth? It’s down to the presence of actor Travis Van Winkle — who plays the same character in both movies, though that fact flew under most people’s radar.

In the 2007 film “Transformers,” Van Winkle plays obnoxious jock Trent, who is dating Megan Fox’s Mikaela when the film begins. She quickly dumps him, but that’s not the last we see of ol’ Trent. Van Winkle turns up again two years later in “Friday the 13th,” playing the exact same obnoxious jock, who this time cheats on his girlfriend. Given the complicated rights issues surrounding the latter franchise, however, don’t expect this to ever lead to a crossover.

Director John Hughes is responsible for a number of iconic ’80s teen comedies, from “Pretty in Pink” and “Sixteen Candles” to “Weird Science.” He’s also the man behind such family classics as “Home Alone,” “Planes, Trains, and Automobiles,” and “Uncle Buck.” But what many may not realize is that a lot of Hughes’ movies all take place in the same fictional town of Shermer, Illinois — and a few of them are even set at the same school, Shermer High.

Shermer High School is called out by name in “Weird Science,” “The Breakfast Club,” and “Ferris Bueller’s Day Off.” The town itself is also the setting in nearly every other movie in Hughes’ filmography. And this is no mere fan theory, as the director himself has confirmed that, yes, most of his movies all take place in the same universe. 

“When I started making movies, I thought I would just invent a town where everything happened,” Hughes told Comcast years later. Noting that everyone from all of his films hails from Shermer, Illinois, Hughes revealed that many of the characters in his films are neighbors. “Del Griffith from ‘Planes, Trains & Automobiles’ lives two doors down from John Bender [from ‘The Breakfast Club’]. Ferris Bueller knew Samantha Baker from ‘Sixteen Candles.’ For 15 years I’ve written my Shermer stories in prose, collecting its history.”

In the mid-1990s, novice screenwriter Charlie Kaufman wrote a borderline abstract comedy-drama about people who live inside another man’s head. It eventually found its way into the hands of another unproven talent — first-time director Spike Jonze — and the result was “Being John Malkovich,” one of the weirdest, most ambitious, and downright risky studio films of the 20th century. In the movie, the head of John Malkovich — who plays himself — is linked to a doorway in an old apartment building that people can pass through and take control of his body.

Nearly 20 years later, comedian Jordan Peele made his own directorial debut with “Get Out,” a psychological horror movie where a young man discovers that an enigmatic family is plotting to transfer their minds into the bodies of various Black people who they lure to their homestead. Right away, you can see how viewers of both films might take the two stories and link them together in a kind of fan-driven head-canon. That Catherine Keener stars in both films makes it even more intriguing.

The theory goes that Keener’s character in “Being John Malkovich,” Maxine, is the same character she plays in “Get Out,” with a new name to hide her identity. But this became more than just fan fiction when Peele declared it official: “Get Out” is a sequel to “Being John Malkovich.”

If you’ve never heard of either of these movies then you’re in for quite a history lesson. Both are B-movies and indie classics of a sort, with “Chopping Mall” being a darling of ’80s cult horror fans. That film, from 1986, follows a group of rowdy, sex-crazed teens who spend a night partying at a local mall after hours. They soon learn, however, that the mall is watched over by a new breed of security system with a screw loose, and before long they’re picked off one by one by three out-of-control killer robots.

The 1982 film “Eating Raoul” is an indie black comedy featuring Ed Begley Jr., Buck Henry, and future “Star Trek: Voyager” star Robert Beltran. The real stars, though, are Paul Bartel and Mary Woronov as an uptight older married couple who get involved in the swinger scene as a means to fund their newest business venture by robbing and murdering the wealthy sex game participants.

The two films have little in common story-wise, though both are very darkly comedic. Yet that’s not all that connects them, because in an early scene in “Chopping Mall,” Bartel and Woronov appear as their “Eating Raoul” characters, who are present during the kill-bot’s first demonstration. It’s a left-field cameo that most viewers probably didn’t even get, and it’s even more perplexing to see Paul and Mary get the limelight in the scene, remarking about the strange robots to each other in a scene that feels like a dark in-joke.

In just his second directorial effort, James Gunn crafted “Super,” a gritty 2010 superhero comedy about an average man (Rainn Wilson) who has a religious awakening and decides to fight crime on the streets as a costumed vigilante called the Crimson Bolt. Darkly comedic in Gunn’s usual style, “Super” was genre-shaking even if it wasn’t a blockbuster hit, turning Gunn himself into a sought-after talent and laying the groundwork for “Guardians of the Galaxy” and the new DCU. 

In 2017, Gunn produced another superhero movie, “Brightburn,” that was less comedic and even darker, as the story followed a young boy from outer space with superpowers who doesn’t use his abilities for good. It was a more twisted take on the Superman mythos, years before Gunn was enlisted to write and direct “Superman” for DC. But “Brightburn” was also part of its own shared cinematic universe, with a clear connection to “Super.”

That connection comes during the closing credits, where news arrives of various super-powered incidents from around the globe. While one mentions an undersea monster and another references a super-powered witch, a photo of Rainn Wilson’s “Super” character, the Crimson Bolt, is also shown. Sure, this was probably just a fun bit of world-building — some might even argue just an Easter egg — but it raises a lot of interesting possibilities when one considers a potential a “Brightburn” sequel (even if Gunn says it may never happen).

We know that the first “Transformers” film is connected to the “Friday the 13th” remake by way of the smarmy jock Trent. But there’s another, less talked about connection to the “Transformers” movies, and we’re not talking about “G.I. Joe.” We are, in fact, talking about the 2000 romantic comedy “28 Days,” starring Sandra Bullock — not the most obvious movie to consider sharing a universe with “Transformers,” especially given that it was released seven years before the Transformers made their live-action debut.

In that movie, Bullock plays an alcoholic forced to endure 28 days in rehab. There she meets a motley crew of fellow addicts, one of whom is played by Alan Tudyk of “Firefly” fame. His name is Dutch Gerhardt, and you’d never have guessed it at the time, but the same character turns up more than a decade later in “Transformers: Dark of the Moon” — at least, so says the actor.

“He’s the same guy. Not only does he kind of seem like the same guy — he’s the absolute same guy,” Tudyk told AV Club in 2014. “He’s changed his name. He went through rehab, and he got into the armed forces, he met up with Agent Simmons. He became a contract killer, he’s overthrown governments in the third world. And then he got burned out and decided the only thing that he could do with his life was to devote himself to working with Agent Simmons, who’s played by John Turturro.”

If you or anyone you know needs help with addiction issues, help is available. Visit the Substance Abuse and Mental Health Services Administration website or contact SAMHSA’s National Helpline at 1-800-662-HELP (4357).

Following “The Fast and the Furious” and “2 Fast 2 Furious,” Universal Pictures opted in 2006 for a spin-off, “The Fast and the Furious: Tokyo Drift,” directed by Justin Lin. Set in Japan, the film features actor Sung Kang as an old friend of Dominic Toretto named Han Lue. Savvy viewers, of course, recognized something that most of us didn’t at the time: Han was not a new character, and he originated in an entirely different, unrelated movie from years earlier.

Justin Lin made his solo directorial debut in 2002 with the movie “Better Luck Tomorrow,” which followed a group of discontented Asian-Americans who turn to criminal capers out of sheer boredom with their mundane lives in Los Angeles. Watch today and you’ll see Sung Kang starring in the film as Han Lue, alongside Parry Shen, Jason Tobin, and John Cho.

A few years later, when Lin was tapped to direct the “Fast and the Furious” spin-off, he brought Sung Kang and the character of Han with him. Since then, Han has become a fan favorite, so much so that following his death in “Tokyo Drift,” the film was retconned to take place after other movies in the series, allowing Kang to return — which he did four more times before it was revealed in “F9” that he wasn’t dead at all.

The “Alien” franchise has famously crossed over with the “Predator” franchise for two feature films, while both series are littered with other connections to each other — often through the existence of the Weyland-Yutani Corporation. This megolithic corporate entity funded the research into the “Alien” saga’s Xenomorphs, and is even name-dropped in the 2025 film “Predator: Badlands.”

That same reference, however, can be found in a more unlikely place: The 2010 action movie “Death Race 2” (the prequel to 2000’s “Death Race”), starring Luke Goss. The “Death Race” films are set in a dystopian near-future where all prisons are privately owned and convicts are forced into deadly races for the amusement of the masses. In “Death Race 2,” we learn that the Terminal Island Penitentiary, where the films are largely set, are funded and owned by — you guessed it — the Weyland Corporation.

Officially, it’s unlikely the two franchises are truly connected to the point where they’d ever cross over on-screen — we’re unlikely to see Goss’ “Death Race” hero battling a Xenomorph, for example. But it’s more than just a tip of the hat, as director Paul W.S. Anderson also directed the first “Alien vs. Predator” film, and it seems clear that, at least in his mind, the two worlds are connected. 

“Collateral” and “The Transporter” have a lot in common: Both are exciting action thrillers, both are headlined by a badass action star, and both feature a complicated criminal-for-hire as their protagonist. Both films also have some serious talent behind the camera, with “La Femme Nikita” director Luc Besson penning the script for “The Transporter” and “Heat” helmer Michael Mann sitting in the director’s chair for 2004’s “Collateral.” So while many may not know about their connection, the fact that they take place in the same world makes a lot of sense.

In “Collateral,” Tom Cruise plays Vincent, a shadowy hitman who ropes an unsuspecting cab driver into his latest mission. Two years earlier in “The Transporter” (and later in its two sequels), Jason Statham portrayed Frank, a one-man wrecking crew who makes a career out of being a high-level criminal courier. But even though “Collateral” is set in Los Angeles and the “The Transporter” takes place in Besson’s native France, the two actually come face-to-face in a pivotal scene in “Collateral,” as an unnamed courier played by Statham delivers a mysterious package to Cruise’s Vincent. 

Statham’s role is uncredited, so it’s easy to assume that this was just a coincidence, but “Transporter” director Letterier has acknowledged that they are the same character, even pondering at one point the possibility of Frank popping up in more movies from Michael Mann. 

Movies can share a universe via on-screen cameos, casual mentions of another franchise’s characters, or even a background detail that links them together. In the case of “Commando” and “Die Hard,” it’s the presence of a single, fictional location: the Latin American nation Val Verde. In 1985’s “Commando,” Val Verde is the location of John Matrix’s (Arnold Schwarzenegger) next mission, as he’s hired by its villainous leader Arius to assassinate his enemies. But Matrix never makes it to Val Verde, as he betrays Arius and goes on a personal mission of his own.

Val Verde turns up again in, of all places, in 1990’s “Die Hard 2: Die Harder.” In the film, John McClane (Bruce Willis) goes up against the current dictator of Val Verde, who is being extradited to the U.S. to face trial. It might seem like an odd callback, but the presence of Val Verde in the “Die Hard” sequel is probably due to the fact that one of the men who wrote it also penned “Commando”: screenwriter Steven E. de Souza.

What’s strange is that Val Verde is only ever seen once on-screen, and it isn’t in either movie: Val Verde is the primary setting for Schwarzenegger’s 1987 classic, “Predator.” De Souza wasn’t even involved in that film, but nevertheless, three of that era’s most iconic action movies all take place in the same universe.

Although we aren’t really considering fictional movie universes that originate in parody films, we’re including “Scream” because — while it has been described as a satire of the horror genre — it’s more of a black comedy with a sense of self-awareness. So here’s a lesser-known crossover that you may have forgotten: Jay and Silent Bob’s appearance in “Scream 3.”

In that 2000 threequel, things get truly meta as the film visits the set of a movie-within-the-movie: “Stab 3,” the third film in a trilogy based on the murders committed by the Ghostface killer from the first “Scream” entry. Set in Hollywood, “Scream 3” itself provides audiences with several surprise cameos, including “Star Wars” star Carrie Fisher and B-movie director Roger Corman both playing themselves. Not playing themselves, however, are Jason Mewes and Kevin Smith, who turn up on the backlot during filming as their “Clerks” characters Jay and Silent Bob.

It may seem like an odd cameo, but just a year later, the pair headlined their own movie, “Jay and Silent Bob Strike Back!” which takes the duo back to Hollywood. This time, they’re looking for vengeance after a studio attempts to make a movie out of “Bluntman and Chronic,” the in-universe comic book based on their likenesses.

We may be cheating a little with this one, since both “Luther” and “The X-Files” are primarily TV properties, although both spun off into movies as well. But what makes the connection between these worlds noteworthy is how they are linked, because they are also two of the less-heralded entries in the Richard Belzer-verse.

Richard Belzer played Detective John Munch for decades on TV, most famously in the crime dramas “Homicide: Life on the Street” and “Law and Order: Special Victims Unit.” He’s also appeared in a number of other shows as well: He pops up in “The Wire” and “Arrested Development,” and even makes animated and puppet appearances in “The Simpsons” and “Sesame Street,” respectively.

Though he isn’t mentioned in the film “Luther: The Fallen Sun,” Munch does get name-dropped in an episode of the “Luther” series as a New York compatriot of Idris Elba’s embattled British copper. But Belzer did play Munch on-screen in “The Unusual Suspects,” a 1997 episode of “The X-Files” that takes Mulder (David Duchovny) and Scully (Gillian Anderson) to Baltimore, where Munch is interrogating a witness prior to his move to the Big Apple. The strangest connection of all is “A Very Brady Sequel,” where, in an appearance played for laughs, Munch shows up to investigate Carol’s (Shelley Long) first husband Roy (Tim Matheson).