We never saw that coming... The best surprise TV crossovers of all time

There's nothing quite so enjoyable as seeing a characters from a completed unconnected TV show turn up in your favourite series. Did you know Alf popped up in an episode of Mr Robot season two? Or sitcom Mad About You is connected to Friends?(Phoebe's twin sister Urusla is in both shows) What about Walter Bishop in Fringe wearing the multi coloured glasses he got from his friend Doctor Jacoby, from Twin Peaks?

The TV landscape is filled with surprise crossovers, suggesting all number of shared universes between TV shows - just google Richard Belzer's Detective John Munch from Homicide: Life on the Street and Law & Order and you'll discover that he's been in The Wire, 30 Rock, Arrested Development, 3rd Rock From The Sun and The X Files. Are they all connected? It seems Fox Mulder only had to ask Munch to get all the answers to alien life he needed.

So what makes a great TV crossover? In this article, I'll look at five the biggest and weirdest surprise crossovers of all time. I saw weird, because I'm excluding confirmed shared universes. No Buffy the Vampire Slayer turning up in Angel or Arrow's Oliver Queen being the best man at Barry Allen's wedding in The Flash. The same for Star Trek, (as much as I would have liked to have added Star Trek: Deep Space Nine's Trials and Tribble-Ations to the list), though Riker turning up Janeway's ready room in Star Trek: Voyager was almost as odd as his appearance derailing the Star Trek: Enterprise finale.

Here then, are five unexpected but rather brilliant crossovers that you might not have seen coming...

The Simpsons / 24: 24 Minutes

The Simpsons has had plenty of great crossovers, from the obvious (Futurama), to a play on The X-Files in The Springfield Files and the much anticipated Family Guy crossover in The Simpsons Guy. But the best surprise crossover feature a character from another show has to be Kiefer Sutherland voicing Jack Bauer from 24. It's no surprise this episode often appears in the various best TV crossover episode lists (of which, this article is no different).

24 Minutes is a brilliant spoof of 24, right down to the ticking clock real-time format and tension packed-sequences (Marge realising she has 27 minutes to bake a cake for the school bake sale is a real highlight). Bart and Lisa become the heroes to the story heading up Principal Skinner’s Counter-Truancy Unit (CTU), crossing paths with Jack Bauer (Sutherland) and Chloe O’Brian (Mary Lynn Rajskub) in a dramatic call to stop a bomb exploding. Playing exactly like an episode of 24, 24 Minutes is one of the funniest and surprising mash ups of two TV shows ever committed to screen.

Bones / Sleepy Hollow: The Resurrection in the Remains / Dead Men Tell No Tales

We were all surprised when a crossover was announced between kooky crime procedural Bones and the overtly supernatural Sleepy Hollow. Even more surprising was how it worked. Fox went for possibly the weirdest crossover ever as it mashed both shows together and saw Temperance Brennan (Emily Deschanel) and Seeley Booth (David Boreanaz) working together with Abbie Mills (Nicole Beharie) and Ichabod Crane (Tom Mison).

The fun, slightly fish-out-of-water aspect of these two episodes aside, this biggest success is in how both sides of the story work. The Bones episode, The Resurrection in the Remains feels like a Bones episode, only hinting at the supernatural elements of the other show, while Sleepy Hollow's Dead Men Tell No Tales ramps up the horror without ever making the presence of Brennan and Booth feel ridiculous. While the shared crime solving-aspect of both shows provides a constant narrative theme, the Bones / Sleepy Hollow crossover showed how two distinctly different shows could still work together without sacrificing what makes each of them unique.

The X-Files / Cops: X-Cops

Season seven of The X Files may have seen the show running out of steam (though season eight revitalised it for a while), but there was one clear highlight in that run that stands out for being oddly unique and experimental. The concept is terrific; what if Mulder and Scully wandered into an episode of reality TV show Cops while tracking a monster in downtown LA?

X-Cops is a ridiculously fun, tongue in cheek episode that plays up the  characters's attributes; Mulder recanting tales of mythological monsters to the raised eyebrows of the local police force or Scully getting increasingly frustrated at the camera crew following her every move. The nature of the 'fear monster' means that we never see it on screen, though the wild and varied descriptions (a werewolf, Freddy Kruger) offer plenty of tension and humour as the episode builds to it's The Blair Witch Project-style climax in the house. It is an episode that is both a great entry into The X Files, but just gritty and real enough to be believable the two intrepid FBI agents could have actually wondered into a reality TV nightmare...

Crisis on Infinite Earths (Parts 1-5)

The annual Arrowverse crossovers are always the highlight of the TV calendar and the current season's team-up of Arrow, The Flash, Supergirl, Legends of Tomorrow and new series Batwoman was certainly the biggest yet. With infinite realities being wiped from existence, the stakes were high and with them, the opportunity to visit a whole host of TV and film comic-adaptions, making this far more than the standard crossover between all five The CW DC shows.

What made Crisis on Infinite Earths so much fun, was the joy of seeing our favourite characters turn up in the worlds of other shows completely unconnected to the Arrowverse. From Burt Ward appearing as an elderly version of Dick Grayson / Robin from the 1960's Batman to a trip back to Smallville, the old cancelled Birds of Prey TV series and even a on-screen encounter between the Flashes of the TV and movie universes, as Grant Gustin's Barry Allen met Ezra Miller's version from the big-screen Justice League. Perhaps the most fun and surprising off all was John Constantine heading to Earth 666 to seek help from Tom Ellis's Lucifer. Crisis on Infinite Earths was a massive celebration of comic book shows and films, with some of the wildest crossovers ever committed to the TV screen.

Supernatural: Scoobynatural

Sam and Dean Winchester joining forces with the Scooby Gang to fight monsters? It's an idea that already sounds ridiculous before you discover that 90% of the episode is in animated form - Dean (Jensen Ackles), Sam (Jared Padalecki) and Castiel (Misha Collins) working with Scooby Doo and the gang to spend a night in a haunted house in a replay of 1970 episode A Night of Fright Is No Delight.

Scoobynatural is not afraid to make the most of its kooky premise. Dean has the time of his life, whether it's enjoying ridiculously oversized sandwiches with Shaggy and Scooby or flirting with Daphne. But the highlight has to be the moment Sam and Dean convince the Scooby gang that monsters are real, sending them into a catatonic state of trauma, before bringing it all back for one great chase sequence and unmasking. Just as clever is Supernatural's ability to make Sam, Dean and Castiel getting pulled into an episode of Scooby Doo via a haunted TV still feel believable to the reality of the show. Supernatural had had plenty of great comic episodes, but few have even been as fun as this ludicrously fun TV crossover.



What are you favourite TV crossovers? Are these entries big and fun or just plain ridiculous? Let us know in the comments below. And if the multiple Detective John Munch appearances have peeked your interest, just google The Tommy Westphall Universe and prepare to have your mind blown...