If you're looking for a film that will leave your head spinning, Shutter Island is a good place to start.
The epic plot twist in the 2010 psychological thriller left us all reeling the first time we watched it - so much so, that a lot of viewers went back for seconds, and thirds.
Which is how this movie buff managed to spot a series of 'major clues' which were slipped into the opening scenes that went over most peoples' heads. Check out the trailer here:
Film fanatic Alex, better known as StarkVerse online, shared a TikTok video breaking down all the subtle hints in Shutter Island which signalled that not everything was as it seemed.
Leonardo DiCaprio starred as US Marshal Edward 'Teddy' Daniels, who heads out to a hospital which houses the criminally insane in search of a patient who has vanished.
He is accompanied by his so-called partner Chuck Aule (Mark Ruffalo) and ends up having quite the terrifying experience as he investigates the disappearance.
However, viewers were left open mouthed when the truth emerged at the end of the film.
It turned out that DiCaprio's character was actually on a wild goose chase, as he was in fact a patient at the creepy hospital himself.
DiCaprio's 'seasickness' in the opening scene was down to something else, according to Alex (Paramount Pictures)
The 'investigation' was a farce - which everyone on the island was in on - that was arranged by Dr. Cawley (Ben Kingsley) as a sort of role-play therapy to help him confront his past.
It's safe to say a few of us dropped our popcorn when we realised DiCaprio wasn't the hero after all - but it turns out there were a ton of tip-offs littered in the opening scenes.
According to Alex, it 'took him 14 years' to cotton onto all of this clever foreshadowing, so don't get disheartened if you never managed to pick up on them yourself.
In the video, the social media star explained: "It's a movie that definitely rewards multiple viewings.
"It's an entirely different experience watching this movie when you know all the twists at the end, because there are so many big clues very early in the film that are mind-blowing.
"Like in the beginning of the movie, we can see Teddy taking a ferry to Shutter Island and we can see him not feeling well. And he thinks this is because he is seasick - but actually, the ocean water reminds his brain of what his wife did to his kids."
There's the first bombshell for you...but Alex reckons the boat journey to Shutter Island is brimming with even more nods to the plot twist, too.
Clues hinting at the epic plot twist are littered in Shutter Island (Paramount Pictures)
He continued: "Then he goes up on the deck and he meets Chuck, and Teddy doesn't think it is weird that he meets the only other US Marshal on the boat - when in reality, they would have gotten on the boat together.
"It's so easy to accept this just as 'normal' for the audience, but then when they arrive on the island, if you pay attention to the guards, all of them tense up almost as if they would be afraid of Teddy."
Alex concluded by discussing the 'most obvious' clue which was inserted into the beginning of Shutter Island, which occurs when Teddy and Chuck arrive at the hospital.
He went on: "When they are entering and they're asked to take off their firearms, we can see Chuck is struggling to take his off, which should have told us right away that something is wrong here."
As we later discover, Chuck is a psychiatrist rather than a detective, so he's not experienced with handling guns and can't coolly remove it from his holster. Incredible, right?
Social media users seemed to think so, as they flooded the comment sections with their thoughts on Alex's observations.
One said: "I have always said, Shutter Island is two movies. On the second viewing, the story is completely different."
Another wrote: "I am 100% sure that Shutter Island is an aftermovie of Inception."
While a third added: "I finally watched this movie. When the plot twist came - until this day, there's no plot twist that got me like this. Best plot twist ever. Makes you jump out your seat type energy."
Does anyone else fancy sticking Shutter Island on?