Horror is one of the most primal genres to exist. It touches the primitive parts of our minds that still fear what we cannot see in the dark and how it will hurt us. However, a lot of modern day horror focuses less on building to those moments in favor of the instant-gratification emotions of a jump-scare. Novels don’t have the sound and visuals that will shake someone as quickly, so how do we get the most out of the gruesome things that people read?
One way to approach the pacing of a horror novel is to write it like a mountain. The mountain depends on the author building suspense to the reveal of the monstrous elements of their story. It starts mundane, introducing the audience to our protagonist and the mundane of their lives, but there are small things that are out of place. Walking the tightrope of the Uncanny Valley is key to holding tension through a novel; making sure to unsettle the audience just enough to know something is off about that loose floorboard or the little boy in the house next door that stares into their window each night, but also not showing their hand to the audience until the last minute. This is extremely effective for psychological horror and thrillers.
The tension can be stretched through the length of the novel, but this can only be done for so long and is a bit tricky to pull off. Drag on for too long, and the reader grows bored, but act too prematurely and your novel will not have the impactful ending that will keep readers thinking about it long after.
You may also want to write the horror a bit more sporadically, like driving down a winding road on a cliff and looking down into the valleys below. The cliffs and gorges style approaches horror in a much more jarring pace, the terror jumping out of the shadows and vanishing within a heartbeat. These jagged peaks are interspersed with dips, giving the reader time to catch their breath and learn more about what may really be going on in the dark. It plays its pacing much faster, often showing nightmares from possessed children who may have never been possessed, to masses of organs and limbs crawling down a hallway that turns to be an illusion of items piled in a hallway in the dark, until we learn that there is a creature reaching through the protagonists psyche and will kill them with these visions or drive them to insanity. This is the style that you will often find in supernatural and science fiction horror with story elements that are allowed to be more chaotic and impossible than the inhuman acts that humans may instigate.
But even this must build to something; a horror novel cannot start with the large battle against the true antagonist of the story and be expected to hold the same tension as a story that ends with that struggle.
Pacing horror can be one of the most difficult balances to strike in writing the genre, a constant mind-game of mapping out the struggles of what your characters will face while also tapping into what the audience would find terrifying. Horror is a unique genre that could have very well been the first stories told before written record. Our ancestors were terrified of death, sickness, animals, and anything they didn’t understand, and even today these things scare us in a world where we understand so much more. But even now these stories are told and they will still shake us to our core and haunt us when we stare at our ceilings in the night, wondering about what lurks under our beds.