Summer is over. Nights are stretching out, and days are growing colder. Leaves are falling from the trees.

It’s the time of year for Halloween stories.

But what makes a story scary? What is it in these tales that makes us shudder or gasp? How do scary stories work?

Trying to answer those questions in a thousand words or so is impossible, but I have a few general thoughts on this. I’m going to focus on a couple of films, but this all applies to books as well‌—‌I’ve kept these thoughts close while writing my own sci-fi/horror series. The films I’m going to mention most are Alien and An American Werewolf In London, and there will be spoilers below.

Normality

Scary stories are usually fairly extreme‌—‌undead creatures, different realities, powers that run counter to how physics tells us the world works. For this to have an impact, there needs to be something we can relate to. Horror is always worse when it is played out against an everyday backdrop. The creepy haunted house can work, but only if there is some kind or normality about it. Take Stephen King’s The Shining‌—‌the setting might be a large, seemingly empty old building cut off from the rest of the world, but it’s also a hotel, where people go to relax and enjoy themselves.

But the more mundane the setting, the greater the impact of the horror elements. The Exorcist is set in a normal house, with a single-parent family. In Poltergeist and Ring, TVs play an important part. Then there are the stories where dolls come to life and cause havoc, like Chucky in Child’s Play.

Why does this work well? Because we’re used to the normal stuff. We’ve probably all had good times in a hotel. Many of us live in regular houses. We watch TV. Our children have dolls and other toys. And in a scary story, these normal settings and objects take on new, frightening aspects.

In American Werewolf, we start on the Yorkshire Moors (slightly creepy because it’s night-time, but still relatively ‘normal’), and then go to London. It is relatively easy to imagine a monster stalking a dark, misty moorland, but surely not in a modern city.

Even a space-ship can seen normal. In Alien, there are no shiny control panels, and things look used. The crew are workers, and we can relate to them‌—‌yes, they might be in outer space, but they’re just doing a job. They’re just like us.

That familiarity helps us relate to what is happening in the story, but it also forces us to see our own surroundings in a new light. When a werewolf is staking people in a city, we start to wonder what that noise coming from outside might be. When toys come to life with murderous intent, those glassy eyes in the bedrooms of our children send a shudder down our spine.

Imagination is scarier than reality

Scary stories work best when things are left to the imagination. When all we are presented with is shadows, and maybe some kind of noise, our minds fill in the blanks — and our minds know just what terrifies us.

In Alien we don’t see the complete monster until the very end of the film. We see parts of it, in shadows. We see what it leaves behind. We see some of the characters’ reactions to it. But we don’t come face to face with it for a long time.

That’s one of the reasons the sequels don’t work as horror films‌—‌we see too much of the aliens. By the time we get to Alien Resurrection, and have two xenomorphs swimming effortlessly towards the camera, we know what to expect, and there is nothing like the same sense of dread.

Jaws works the same way (and that film borrows heavily from the horror genre). We never see any part of the shark until the second half of the film, and even then only see the whole thing near the end.

In both cases (Jaws and Alien), some of this was down to practicalities in the film-making process — there were not the resources to effectively show the whole monster. But the film-makers used this limitation to their advantage. Rather than try to show us everything, they left it up to us to create our own monster.

This is a classic case of ‘less is more’, and I’d like to give another example. In the original version of The Grudge, there is a scene with the main character having a shower, and a hand appears, rubbing her hair. There is no indication where this hand comes from — it’s suddenly there, touching her. She’s in the shower (an enclosed space) and she’s naked (and vulnerable), and suddenly there’s something else in there with her.

This scene doesn’t work as well in the American remake. Here, we get to see the hand growing from the back of the main character’s neck before it touches her head. This is grotesque, but it’s not nearly as scary as the original‌—‌precisely because what we don’t know can be worse than what we see.

Those who tell good scary stories understand that less is more, and that when our imagination is left to fill in the blanks, it taps into our own fears to conjure up something personally terrifying.

Anticipation is vital

Something jumping out and going ‘boo’ might make us jump, but that fright is gone as quickly as it appears. For longer-lasting terror, there has to be a build-up. There have to be small clues that tell us ‘something’s not right’. The dread must creep up on us, like dark mist, until we suddenly realise that we are being smothered.

The Monkey’s Paw is a great example of this. (Again, there’s going to be spoilers. If you haven’t read this story, it’s in the public domain, so you should be able to get hold of a copy for free. Check out Project Gutenberg.) The monkey’s paw grants wishes, and at first that seems like a good thing. But the old saying ‘be careful what you wish for’ holds true here. The couple who find the paw wish for money, and it duly arrives‌—‌as compensation for the death of their son in a workplace accident.

This is the set-up. We learn that wishes come at a price.

The mother wants her son back. The father had to identify the body, so he knows just what the accident did to their son. He tries to stop his wife, but she grabs the paw and makes her wish.

There’s a knock at the door. The mother races down the stairs, and struggles to free the latch. Meanwhile, the father is scrambling around, dreading what will happen when his wife sees the abomination at the door. She’s thrown the monkey’s paw down somewhere, and he has to find it. He needs to stop what’s about to happen.

We never get a description of the son, but that doesn’t matter. We can imagine it (again, the power of imagination), but what gets our hearts pumping is the race between the mother and the father, and the fear of what will happen when she opens the door.

It is the anticipation that drives the horror.

I’ll give another example, from one of the most memorable sequences in American Werewolf. We see a commuter stepping off a tube train. The train disappears into the tunnel, leaving him alone on a platform. He hears a noise, but he thinks nothing of it, and he carries on his way. The noise repeats, and he calls out, telling whoever it is that he doesn’t find this funny in the slightest. But there is definitely something around. He starts to get nervous. He walks faster, and then he starts to run.

We do see the werewolf, briefly, but by that time the commuter has collapsed on an escalator. The werewolf appears at the bottom, and starts to climb. We cut back to see the commuter, as he watches this thing approach, and the terror grows on his face.

I can’t remember if we see the attack. But I can remember the build-up, because that is the scary part.

The false ending

This occurs in thrillers a lot, but works very well in horror too. It’s usually the moment where everyone in the cinema jumps out of their seats at the same time.

There’s an example part-way through American Werewolf, in a dream sequence. The main character watches his family being slaughtered by monster-soldier things, and when one of them pulls a knife across his throat he wakes up with a jerk. He’s in his hospital bed, with a nurse watching over him. It was only a dream. The nurse, seeing he’s awake, goes to open the curtains.

And as she reached the window, one of the monsters leaps out and stabs her in the chest.

It’s a shock because we never for a moment suspect that he’s still dreaming.

Alien saves the false ending for the final moments of the film. Ripley sets the Nostromo to self-destruct, then races to reach the escape pod (after finding the ship’s cat, of course). There are sirens blaring, and lights flashing, and the alien is somewhere on the ship. It’s a great sequence, and when she finally seals herself into the escape pod and ejects, and the Nostromo explodes, we feel her relief.

And then something moves in the shadows. She has not destroyed the alien. It is in the escape pod with her.

False endings are often the most memorable parts of stories. We already have the build-up of adrenaline in the tension-filled scene before, and then we have that fake release, followed by the sudden shock that makes our hearts leap.

It’s the perfect scare.

So there you have a few reasons scary stories work. Of course there are more (like the fate worse than death, and the corruption of innocence), and I’m interested on your thoughts on this. What gets your heart racing in a story? What makes you jump out of your skin in a book or a film?