The unknown is a big factor. For example, when a sleepwalker goes to a strange or dangerous place like a cliff or an abandoned building while asleep. It's scary because we don't know what might happen to them.
Violent actions during sleepwalking can be terrifying. If a sleepwalker starts acting as if they are attacking someone or something, it gives a sense of danger. Also, if they are in a trance - like state and seem unresponsive to the outside world, it adds to the scariness. Like in the story where a sleepwalker with a knife in hand was just chopping randomly. It makes you wonder what could go wrong.
The fact that the sleepwalker has no control over their actions and no memory of what happened during their sleepwalking episode can be quite terrifying. It's as if their body is being controlled by some unknown force. In some stories, a sleepwalker might do things completely out of character, like writing strange messages on the wall or standing in a menacing pose, which is really spooky when they have no recollection of it later.
One element is the setting. Dark and isolated places like an old cemetery or a haunted house can be really scary. For example, a story set in a derelict asylum where the walls are crumbling and there are strange noises coming from the empty rooms. Another element is the unknown. When there are things that the characters (and the readers) can't explain, it creates fear. Like a strange figure that disappears when you look directly at it. Also, the use of suspense. If a story builds up tension slowly, for instance, by having a character hear footsteps getting closer and closer but not knowing what's causing them, it makes the story scarier.
Once, I heard about a man who would sleepwalk every night. One night, his family heard strange noises from the kitchen. They found him sleepwalking, with a knife in his hand, chopping at the air as if fighting an invisible enemy. His eyes were open but glazed over. It was terrifying as they were afraid he might accidentally hurt himself or someone else if he woke up suddenly while still in that state.
One element is its appearance. For example, if a dog has matted fur, bloodshot eyes, and bared teeth, it immediately looks menacing. Another is its behavior. If it growls constantly, stalks people, or chases them without any obvious reason, that's scary. Also, the context matters. If the dog is in a spooky place like an old, abandoned building or a dark forest, it adds to the scariness.
A sense of impending doom is a great element too. If the characters in the story keep getting signs that something bad is going to happen, like in a story where a family keeps finding dead birds on their doorstep before a series of strange events start to occur. This makes the readers or listeners feel on edge and scared.
A key element is the build-up of tension and suspense. When you don't know what's coming next, it keeps you on the edge of your seat.
One element is the unknown. When things are not clearly defined, like in a story where there's a strange noise in the dark but you don't know what's making it, it creates fear. Another is the sense of isolation. If the character in the story is alone in a spooky place, like an old house in the middle of nowhere, it amps up the scariness. Also, the use of the supernatural, such as ghosts or demons, can be really terrifying.
Unnatural features can make a doll scary. Such as long, sharp fingernails on the doll's hands, or a strange mark on its body. The way the doll is dressed can also contribute. A tattered, old - fashioned dress that is stained can be quite disturbing. And if the doll has a smell, like a musty or rotting smell, it makes the story even more frightening. The interaction between the doll and the characters in the story, like the doll causing harm to them, either physically or mentally, is another factor that makes a doll scary in a doll scary story.
Well, the atmosphere is crucial. A good scary campfire story often has a setting that is either very dark or has an eerie stillness. For example, a campsite near a cemetery or a place where there have been mysterious disappearances. Unnatural events are also great elements. Such as objects moving on their own, like a camping chair suddenly sliding across the ground for no reason. And the characters' fear reactions can enhance the scariness. If they start to see things that others can't, or if they feel a presence that can't be explained, it makes the story more intense.
One element is an unexpected change in the familiar environment. For example, if a person comes home and finds furniture moved around or things out of place without explanation. Another element could be strange noises. Like creaking floors or whispering sounds when no one else is supposed to be home. Also, the feeling of being watched. Even if there's no one visible, that sense can create a lot of fear.