Jaw-droppers. Game-changers. It's so rare for a TV show to actually pull off a shock twist in this age of social media, set spies and spoilers, that when one does land, it's a wonderful thing.
From Game of Thrones to South Park, here are some of the very finest examples of when a TV show took us completely, wonderfully, by surprise...
Serious *SPOILERS* to follow.
1. Ned loses his head – from Game of Thrones
HBO's world-conquering fantasy delivers more stunning twists than any other TV show on the air right now – from the Red Wedding to Jon Snow's resurrection, GoT has made bloody big bombshells its trademark.
But this was the first – and so by definition, the most surprising. Who knew – in the innocent days of 2011 – that the show would spectacularly axe its biggest star?
We've since grown accustomed to such cruelty, but back then, Ned's demise was utterly unexpected and a genuinely astonishing bit of television.
2. "We have to go back!" – from Lost
Lost took a lot of flak over its controversial climax, but when it was firing on all cylinders, the biggest TV show of the '00s was phenomenal television.
One of its finest moments came with the season 3 finale: we'd assumed that scenes featuring a downbeat, beardy Jack (Matthew Fox) were flashbacks – as was the series standard – but in fact, they were nothing of the sort...
The closing twist revealed that we were instead being offered our very first glimpse at Jack's life after the island – dramatically altering the path of the series...
3. Ward is HYDRA – from Marvel's Agents of SHIELD
Agents of SHIELD is often dismissed as the less satisfying small-screen version of Marvel's big blockbusters movies, with even the show's cast hitting out at their bosses for not paying the show enough respect.
But the big reveal in 2014's Captain America: The Winter Soldier – with SHIELD torn apart by HYDRA – was the best thing that ever happened to the show, as square-jawed boy scout Grant Ward (Brett Dalton) was unmasked as a mole who'd been plotting against his pals all along.
Whether or not the twist was actually planned from the beginning, it certainly made Ward – and the entire show – a whole lot more interesting.
4. Brody is a wrong 'un – from Homeland
It's easy to forget, but back in 2011, the true allegiance of Damian Lewis's tortured soldier Nicholas Brody was very much up in the air – and it was that ambiguity which kept us hooked on the early episodes of Homeland.
Was Brody's apparent defection all in Carrie's head? The show toyed with us and kept us guessing for eight long weeks, before finally revealing that he was in fact a terrorist plant. A superbly orchestrated twist, worth the wait.
5. Teri Bauer bites the bullet – from 24
Sure, everyone remembers the shock moment when Nina (Sarah Clarke) was unmasked as a mole in the first year of 24 – but if you really size it up, that particular twist is pretty convoluted and (whisper it) doesn't make a whole lot of sense.
Far superior was the cold-blooded murder of Jack Bauer's wife Teri (Leslie Hope) at Nina's hand in the season finale. No mere stunt, her loss shaped Jack's character across the eight seasons that followed.
6. Number 6 is Number 1 – from The Prisoner
Who is number one? This question hung over all 17 episodes of Patrick McGoohan's psychedelic '60s series The Prisoner, which saw his retired British agent – labelled 'Number 6' – trapped in a sinister village by forces unknown.
The show's outlandish finale, 'Fall Out', saw Number 6 unmask his quarry – only to discover his own face staring back at him, cackling wildly.
Was Number 1 really Number 6? Or a double? Was any of The Prisoner supposed to be real – or just one man's delusion? McGoohan always remained elusive on what the surreal final scenes were supposed to mean...
7. Vic Mackey kills Terry Crowley – from The Shield
FX's superb and sorely underrated cop show The Shield opened with what seemed like a familiar set-up. There's a corrupt cop (Michael Chiklis) out for his own ends, unaware that an undercover operative (Reed Diamond) has been planted on his team by the Feds.
So imagine the audience's surprise when the pilot ended with Diamond's Terry being shot dead by Chiklis's Mackey. There was to be no clichéd game of cat-and-mouse here – and with dirty Vic as its lead, the show continued to defy convention and tell truly unpredictable stories for seven years.
8. Scott Tenorman eats his parents – from South Park
In possibly South Park's greatest ever episode, Cartman is humiliated again and again by a local bully – but Scott Tenorman has picked the wrong 4th grader to pick on...
In the final scenes, it looks as though Scott has got the best of Eric once more. Until it's revealed that Cartman had hatched a convoluted revenge scheme that involved Scott's parents being killed, chopped up and fed to their unwitting son as delicious chili.
If that wasn't terrible enough, he's also arranged for Tenorman's favourite band Radiohead to witness his lowest ebb. Little crybaby...
9. The Tommy Westphall Universe – from St. Elsewhere
Oh, this one's a doozy.
The final scenes of this Emmy-winning medical drama imply that the hospital – and all the people who work there – are mere figments in the mind of an autistic child named Tommy Westphall.
But there's more – a theory known as the 'Tommy Westphall Universe Hypothesis' posits that because St. Elsewhere crossed over with other shows, which then went on to cross over with more shows, and so on and so on, this could mean that literally hundreds of TV series all take place in Tommy's head.
From 24 to Buffy to The Fresh Prince of Bel Air... it was all just a dream. You can check out the entire list here – it's mind-blowing stuff.
10. "How's Annie?" – from Twin Peaks
Twin Peaks delighted in baffling its viewers and defying expectations, but all the same, it shook us up something bad when the final episode revealed that our lead Dale Cooper (Kyle MacLachlan) had been trapped in the sinister Black Lodge and replaced by an evil doppelganger.
The series originally ended on this cliffhanger – but with MacLachlan reprising his role in Showtime's 2017 revival, we finally found out what happened to Coop... 26 years later.
11. Bristow's working for the bad guys – from Alias
Alias had a hell of a pilot, with the show's apparent premise – that Jennifer Garner's Sydney Bristow is a student who leads a double life as a CIA agent – turned completely on its head by episode's end.
Her employers, SD-6? Not part of the CIA, at all, but a terrorist cell. Reeling from the double blow of this discovery and her fiancé's murder at the hands of SD-6 agents, Sydney offers herself up to the real CIA as a double agent, kicking off five seasons of twisty-turny goodness.
12. Lisa Faulkner gets battered – from Spooks
Setting out its stall as an uncompromising spy series like no other, Spooks not only executed Lisa Faulkner – ostensibly a series regular – in its second episode, but did so in the most gruesome manner imaginable.
Her rookie agent Helen had first her hand, then her face, shoved into a vat of boiling oil, before a bullet to the head finished her off.
Grim stuff – and a touch too strong for some, with hundreds of viewers telephoning to complain about the graphic sequence.
