Crossovers are a storytelling shortcut. No matter the medium, combining two fictional properties into one makes it that much easier to interest audiences, since they're already invested in the stories' chief characters. Film and television producers have been making use of this shortcut for decades, but with famously varied and often abysmal results. Because, as it turns out, it's harder than it sounds to meld two fictional worlds into one without undermining some aspects of both. There's always the option of making the crossover non-canonical, but even that doesn't ensure the ensuing episode or film will be entertaining on its own.
Though film crossovers and similar tactics like shared universes have found huge success in the twenty-first century, there are still enough rotten ones among the bunch (Freddy vs. Jason, The League of Extraordinary Gentlemen) to make clear that certain crossover ideas should never see the light of day. The following proposed combinations of separate creative properties represent some of the most ill-conceived crossovers in history, and though some might have miraculously turned out alright, we should probably count ourselves lucky we were spared from ever seeing them.
Check out the 15 Most INSANE Movie & TV Crossovers That Almost Happened.
15 Seinfeld & Friends
On several occasions during their respective runs, NBC sought to combine their two smash hit '90s sitcoms about single friends and serial daters living in Manhattan. None of their proposed ideas ever got any traction, however, thanks to Larry David's firm creative control of Seinfeld. David even rejected the barely-a-crossover concept of NBC's blackout night, in which every New York-set Thursday night sitcom episode revolved around a citywide blackout -- except Seinfeld.
Former Seinfeld writer Peter Mehlman recounted the time David came closest to considering a Friends crossover, however:
Larry immediately said, ‘No way are we doing that.’ And I said to Larry, ‘You know what would be good, though, if we just tell NBC we will do the crossover but in our show Ross would die.’ I think Larry’s arm twitched towards the phone. We had a big laugh about it.
14 Doctor Who & Harry Potter
Doctor Who has been on long enough that it seems the series' writers have thought of almost every conceivable plot for the time-traveling doctor -- including, it turns out, a crossover with Harry Potter. Earlier this year, UK tabloid The Sun reported that, back in 2008, former Doctor Who writer Russell T. Davies proposed an episode to be written by JK Rowling herself and concerning a space bug that infects the famous author and brings her characters to life. The Doctor would have then gone to work putting the characters and creatures back into their respective books.
Even fans of the two beloved British franchises must admit that sounds lame and potentially bogus. But series writer Steven Moffat confirmed that plans for the aborted episode do exist "on a hard drive somewhere."
13 Supernatural & Smallville
The CW's longest-running series Supernatural was on when the channel's most reliable hit was still Smallville, and in fact, there were talks of incorporating the Superman origin story series into a very special episode of Supernatural. Rather than cross paths with young Clark Kent himself, brothers Sam and Dean would have met the actor who plays him instead, Tom Welling, to warn him of his impending doom due to the Superman curse, a real-world legend of actors dying mysteriously after portraying the Man of Steel.
It's an interesting way to do a crossover, but as per usual, would still have ended up undermining the reality of Smallville in some small way. The idea was scrapped, however, and only came to light late last year.
12 Supernatural & Friday the 13th
Yet again, Supernatural almost got away with doing an unconventional approach to the crossover for the third season episode "Dream a Little Dream of Me." This outing follows the protagonists as they go into the dreamscape to rescue a comatose friend, and subsequently experience a series of nightmarish dream sequences. The crossover was to be limited to just one scene, shot in '80s-style film stock, with Dean confronting Jason Vorhees of Friday the 13th fame.
The show was granted permission to use the masked slasher, only for the film studio that gave them permission to realize they didn't actually own the rights for the character. Mere days before filming, the writers were forced to invent a new scene in which Dean fantasizes about a modest family life with a former love interest. It was less flashy, but ultimately, more illuminating to the character.
11 GI Joe & Rocky
At the height of Sylvester Stallone's '80s stardom, the Coleco toy company procured the rights to a children's toy line and cartoon seires based on the bloody post-Vietnam exploits of Rambo from First Blood. In an effort to compete, Hasbro decided to bolster their line of GI Joe action figures with a version of Stallone's other trademark character, Philadelphia underdog boxer Rocky Balboa.
The company's various departments went to work adapting the character to fit into their fictional toy universe, inventing an altered backstory, sculpting an action figure mold, and designing a trading card where Rocky's signature weapon was a stick with a boxing glove glued to either end. He appeared in the background of one comic and might have appeared on the cartoon version of GI Joe, but his agents rescinded the partnership with little explanation.
10 GI Joe & Transformers
Having already met many times in comic book adaptations, these two Hasbro properties very nearly met on the big screen shortly following the second GI Joe live-action film. Director David Caruso spoke earlier this year about his time working on that film's as of yet unmade sequel, saying his script saw the worlds of Transformers and GI Joe colliding in its climax.
But, Caruso says, "they were like, ‘We’re not ready to do this yet.’… They will eventually collide those two worlds and it’s probably when Mr. Bay decides he’s done with Transformers.” Let's hope that day never comes -- for as fun and campy as the old cartoon series may be, it's hard to imagine anything but more meaningless CGI destruction coming from a collision of two toy-based film franchises that specialize almost exclusively in just that.
9 Hellraiser & Halloween
Around the same time that the long-gestating Freddy vs. Jason was finally getting off the ground, there was another showdown between iconic horror baddies in the works, this one pitting mute slasher Michael Myers from Halloween against the sadistic god of pain Pinhead from Hellraiser. Doug Bradley, who played Pinhead, revealed last year that Dimension Films, which owns both franchises, rejected multiple scripts for a crossover, assuming it would fail.
But when Freddy vs. Jason did good business at the box office, the studio got moving on a Hellraiser-Halloween film to be written by original Hellraiser scribe Clive Barker and directed by John Carpenter -- a far higher pedigree of talent than anyone involved in the cheesy Freddy vs. Jason. But alas, the showdown was not to be, as several of Halloween's original producers were allegedly opposed to the idea.
8 Hellraiser & Jay and Silent Bob
As surreal as a Hellraiser-Halloween crossover would have been, it pales in comparison to another proposed crossover featuring Pinhead. Believe it or not, this one would've co-starred Jay and Silent Bob (Jason Mewes and Kevin Smith), the pot-smoking comic duo known for their appearances in Smith-directed films such as Clerks, Mallrats, and Jay and Silent Bob Strike Back. After the release of the latter film, Smith says he received a call from Harvey Weinstein, who suggested Jay and Silent Bob follow the template of Abbot and Costello -- who starred in films opposite famous film monsters like Frankenstein and the Wolf Man after achieving success as a comic pair.
"[Weinstein]'s like, 'I’ve got Hellraiser; I’ve got Children of the Corn, and I’ve got Michael Myers … Halloween. So you put Jay and Silent Bob in with those guys.'" Smith goes on to say his favorite idea was the one in which his characters find the Hellraiser box and are transported to their own personal version of hell -- rehab.
7 Quantum Leap & Magnum PI
Donald Bellisario has had one successful TV series or another on the air for almost every year since the premier of his original hit Magnum PI in 1980. That series, starring a triumphantly-mustachioed Tom Selleck as a private investigator in Hawaii, was almost revived temporarily in 1992 (four years after its series finale) to help boost ratings for the fourth season finale of Bellisario's less popular sci-fi followup, Quantum Leap.
The idea makes enough sense: since Quantum Leap concerns a Dr. Samuel Beckett (Scott Bakula) who can leap through time (within his own lifetime) to inhabit the bodies of other people to correct history, Beckett would simply leap into the body of Magnum PI! The episode was even hyped by NBC before release, but it ultimately never materialized. Quantum Leap was canceled after one more season.
6 Jaws & National Lampoon
Chief Brody had already fought off a maneating great white shark on two separate occasions in the first two Jaws films, so how could audiences seriously believe it would happen a third time? Producers David Brown and Richard Zanuck thought maybe the way to go was by leaning into the comedy with a hybrid sequel-slash-spoof in the vein of Airplane!
They brought on Matty Simmons, publisher of National Lampoon and producer of Animal House, as producer, and he in turn recruited John Hughes (Home Alone, The Breakfast Club) to write and Joe Dante (Gremlins, Pirahna) to direct. The movie was to be entitled Jaws 3 People 0 and feature a bunch of vacuous Hollywood elites in parodies of the earlier series' installments, but the novel idea didn't pan out, and instead we got something much, much worse: Jaws 3D.
5 Game of Thrones & Westworld
A Song of Ice and Fire author George R.R. Martin was the main driving force behind this potential mashup of two of HBO's most buzzworthy current series, the epic fantasy Game of Thrones and heady sci-fi dystopian Westworld. Martin, who seems to be like any fan-fiction-writing fanboy at heart, reportedly suggested to Westworld showrunners Jonathan Nolan and Lisa Joy that they incorporate a Westeros-style theme park into the show.
Joy and Nolan say they were flattered by the proposal, but ultimately refused, in part because they are such big fans of Game of Thrones. "I need to be believe that dragons are real. I want them be a real thing," said Joy. "So as much as I love George, I can’t lose that for myself!”
4 Freddy vs. Jason vs. Ash
A six-issue comic book series debuted in 2007 with the horror nerd-pandering premise of pitting Freddy versus Jason once more, but with chainsaw-wielding Ash Williams of Evil Dead fame thrown in to spice things up. The concept generated enough interest to drum up rumors of a film adaptation, but nothing became of the talks.
Bruce Campbell, who plays Ash in the original films and the Showtime series Ash vs. Evil Dead, revealed why during a Reddit AMA last year: "I’m not real interested in crossovers. One of the main reasons why ‘Ash vs. Jason vs. Freddy’ did not come to pass is because we couldn’t control any other character other than Ash. That felt like a creatively bankrupt way to go. Not to mention, you’re splitting the proceeds three ways with partners you might not want."
3 Scrubs & Arrested Development
Scrubs star Zach Braff was a big fan of the Fox comedy series Arrested Development and even appeared in two episodes as spring break videographer and never-nude Phillip Litt. When the series was cancelled, Braff and Scrubs creator Bill Lawrence both became infatuated with the idea of having David Cross visit Sacred Cross as his AD character Tobias, with Braff saying he wanted to give the character "at least one more life."
Though Cross was reportedly interested, the proposed crossover never went anywhere, probably because Scrubs aired on competing network NBC. Tobias, at least, was eventually revived instead by streaming service Netflix, which produced the fourth season of Arrested Development and is currently financing the fifth.
2 The Beatles & Lord Of The Rings
Decades before Peter Jackson turned J.R.R. Tolkien's fantasy series into an award-winning, game-changing trilogy of epic proportions, there were plans to try adapting Lord of the Rings with the Fab Four cast as the series' main characters to follow up their earlier cinematic efforts in A Hard Day's Night and Help! According to Jackson, who was interviewed on the subject after confirming the story with Paul McCartney, Paul would have played the ring-bearing Frodo, Ringo his loyal gardener Sam, John the villainous junkie Gollum, and George the wizard Gandalf.
The idea was scrapped after their choice for director -- Stanley Kubrick -- turned them down, and Tolkien himself came out against the collaboration. The animated film Yellow Submarine was made instead to fulfill the Beatles' three-picture deal with United Artists, and Jackson gave us three unassailable adaptations. Still, it's hard not to wonder about the Middle Earth-themed Beatles songs we missed out on.
1 Die Hard 24/7
The original title for the sequel that became A Good Day to Die Hard was Die Hard 24/7, alluding to the fact that the film was originally planned as a crossover between the long-running action film franchise and Fox's then-hit action drama series 24, with Kiefer Sutherland's no-nonsense badass Jack Bauer teaming up with Bruce Willis's no-nonsense badass John McClane to fight crime in the most badass of ways.
It's unclear how the two law enforcement officials would have met and what sort of villains they'd be pitted against, as Sutherland soon backed out of the project, saying he'd prefer to star in his own franchise based on 24 (how's that working out for you, Kiefer?). Whatever the story might have been, it seems safe to guess that Die Hard 24/7 would have been as lackluster as the other latter-day Die Hard sequels.
What other insane crossover events almost saw the light of day? Let us know in the comments.