Perhaps it's the people associated with the car in the novel. The driver or passengers might have dark secrets or be involved in something sinister. Their actions and the secrets they carry add to the horror atmosphere of the 'car horror novel'.
The unknown in the car. Maybe there are some unseen and dangerous things lurking in it, like a malevolent spirit that haunts the vehicle.
It could be the situations that occur around the car in the novel. For example, being stuck in a desolate place with the car breaking down while something menacing is approaching. The isolation and the threat combined make it terrifying.
The sense of the unknown. When you don't know what lies in the abyss, it scares you. It's like a black hole of fear that your mind can't fully grasp.
The grotesque descriptions of bones might be one factor. Maybe it vividly depicts the bones in a very eerie way, like they are somehow alive or carry some sort of malevolent force.
The power dynamic. Physicians are supposed to heal, but in these novels, they often use their knowledge for evil. For example, in 'The Strange Case of Dr. Jekyll and Mr. Hyde', Dr. Jekyll's position as a respected doctor makes his transformation into the evil Mr. Hyde even more shocking.
The atmosphere. It probably has a really dark and spooky setting, like an old, abandoned house or a fog - covered forest. The descriptions of these places make you feel like you're there, and it's scary.
The setting of the orchard might be a key factor. It could be a place filled with dark secrets, like an old orchard with gnarled trees that seem to have a life of their own at night. Maybe there are strange noises coming from the orchard, or hidden figures lurking among the trees.
The unknown creatures in 'the ruins horror novel' are really scary. They have strange behaviors and appearances that are not of this world, and the characters don't know how to deal with them. It creates a constant sense of dread.
The visual and disturbing elements in 'ring horror novel' contribute to the terror. For example, the description of the cursed object, like the videotape in 'The Ring' novels, with its strange and often grotesque images. These vivid and unsettling descriptions can haunt the reader's mind, making the horror more real and intense.
The presence of cats alone can be scary in a horror context. They are often associated with mystery and the unknown. Maybe in 'the cats horror novel', they could be possessed or have some sort of evil intelligence.
Well, in a tricycle horror novel, perhaps the tricycle itself is cursed. It could be that anyone who rides it is doomed to a series of horrifying events. For example, it might lead the rider into a nightmarish otherworld where grotesque creatures lurk, and the tricycle is the only means of transportation, trapping the rider in this horror realm.
The grotesque creation of the monster in 'Frankenstein' is a major factor. The idea of stitching together body parts and animating them is deeply disturbing.