The biggest and most brutal twist in Hereditary was hidden in the first half of the movie.

Content warning: this article contains spoilers for the film Hereditary, read on if you dare.

There’s so much to love, and to fear, about new horror movie Hereditary.

Even though we are only halfway through 2018, I think it’s safe to say that it will retain it’s mantle as ‘the scariest film of the year’ for the next six months at least. Once you’ve experienced this story for yourself, it’s hard to imagine another movie that will be able to do anymore than nip at it’s heels.

Hereditary contains a number of bloodcurdling scenes that will casually haunt your dreams for many nights to come once you have left the theatre. It’s not a movie that deals heavily in the grotesque and the obscene, but when it decides to go in that direction, it goes full pelt for the blood and the gore.

The film follows Annie Graham (played by Toni Collette), a woman with a complicated family past who suffers a series of horrific family losses, before an ancient evil takes over her home and begins to destroy her family one by one.

But, what was the most horrifying yet surprising scene of the film was not the moment when Toni Collette’s Annie became possessed and started eerily slithering along walls and manically slamming her head into an attic door while hanging from the ceiling in an attempt to capture her terrified son.

It wasn’t even the moment when her son Peter (played by Alex Wolff), was confronted by a series of leering, naked figures in that same attic, moments after his father succumbed to a fiery death.

The most surprising moment of the film happened when Annie's 13-year-old daughter Charlie (played by Milly Shapiro) was brutally decapitated during the first half of the movie.

The visually disturbing death happened while her big brother Peter was frantically driving towards the hospital while his little sister gasped for air and writhed about in the backseat, all due to the fact that she was having a severe allergic reaction to the peanuts she had accidentally inhaled while at a party her brother snuck her into.

I'd go as far as to say that this is one of the most visually grotesque scenes ever committed to film in recent years, thanks not just to the moment it happens, but also to the fact they were are treated to close-ups of Charlie's decapitated head, laying by the roadside and festering with ants. Along with shots of her headless body, left in the car for her distraught mother to find the next morning.

But it wasn't the brutal way that Charlie died that made this moment so shocking, it was the fact that she died at all.

Death in a film like Hereditary is hardly a surprising story development. From the moment you settle down in that cinema you know for sure that some, if not all, of that family will not make it to the end credits with their hearts still beating.

It's Charlie's death at that particular moment in time that is the real plot twist, although with all the bloody child killing going on at the time you may have missed it.

A lot of fans have been shocked by the scene, some to the point of anger and others to the point where they had to exit the cinema.

In fact, an experiment carried out by Studio A24, where movie-goers were fitted with heart-monitors to check their physical reaction to the film, has proven it to be one of the most terrifying movies in recent memory. The results of the experiment showed that the majority of their heart rates rose to alarming levels while watching the movie, as reported by The Telegraph. 

What was significant about Charlie's death was that she was very much set up to be the film's true and only villain.

She ticked every box relating to what we've come to expect from a creepy child protagonist who turns on her loved ones. While her death was shocking, it was also very much expected that she would return as the films ultimate and only "big bad" at some stage. Yet she never did.

Therefore there was shock at her death, but no real mourning, making her story arc perhaps the most tragically overlooked loss of the film.

In that moment, as her head is ripped off by a utility pole that the car swerves too close to, the movie resets and begins to tell a completely different story.

We switch from facing off against an evil child to facing off against a much more sprawling and deadly force that has embedded itself into this entire family.

It's only now, once the movie has already terrified film critics at festivals and scarred regular movie goers who dared to purchase a ticket, that we know that such an early and surprising twist was intended by the creator all along.

In an interview with Vulture  Hereditary director and screenwriter Ari Aster said the early twist was a punishment of sorts for the audience, for daring to assume they thought they knew where the story was going, and that he himself is tired of being able to guess how the plot of a horror film will unfold.

"I really wanted it to serve as a chute that opens up under the audience and drops them out of the movie that they thought they were watching and into a new movie," he said.

And boy, did he succeed with that.

After all, the ultimate horror of Hereditary is not about what you saw on screen, it's about how those events made you feel as you watched them take place.

The movie takes you to a place where home and family are filled with horrors, to a place where a little girl is seen only as a villain and you are unable to spot the true evil until it is too late.

Sweet dreams.

Hereditary is in cinemas Australia-wide now. It is rated MA15+.

For more stories like this, you can follow writer and Mamamia Entertainment Editor Laura Brodnik on Facebook.