The unknown is a very scary element. For example, in a short horror story, when you hear strange noises but don't know what's making them. It creates a sense of fear and anticipation.
For me, 'The Outsider' by H.P. Lovecraft is extremely scary. The concept of a being that is so alien and terrifying is just bone - chilling. 'The Open Window' by Saki also gives me the creeps. It has a great twist at the end that makes you shiver. Another really scary one is 'The Black Cat' by Edgar Allan Poe. The way the narrator's relationship with the cat deteriorates is truly horrifying.
A very frightening Quora short horror story involves a nurse working the night shift in a hospital. She was walking down an empty corridor when she heard the sound of a wheelchair moving on its own. She followed the sound and it led her to an old, locked room. Through the small window in the door, she saw a patient sitting in the wheelchair, but the patient had died days ago. The idea of a dead patient's spirit still lingering in the hospital is what makes this story so terrifying.
The unknown is a really scary element. In these stories, often there are things like strange noises in the dark that you can't identify. It could be an animal or something more sinister. Another is the feeling of isolation. When you're out in the woods camping, far from help, and something creepy starts to happen, it makes it scarier. For example, if you're alone in a tent and hear scratching on the outside, you have nowhere to run.
The appearance of the doll can be very scary. For example, a cracked porcelain face or dull, staring eyes. It gives an uncanny feeling.
The suddenness of the danger is very scary. In these stories, people are often just going about their normal swim and then, boom, they're in mortal danger. Like in the story of the girl at the lake, she was just swimming and then out of nowhere this unknown force grabs her.
Sudden twists. Like when you think a character is safe and then suddenly they're in mortal danger. In a short story, this can be really shocking. For instance, a person thinking they escaped a haunted place but then finding out they're still trapped in some other way. It plays on our sense of false security.
The element of the supernatural. In quora horror short stories, you often encounter ghosts, demons, or other unworldly beings. For instance, the story of the girl haunted by a vengeful spirit. These supernatural entities operate outside the rules of the normal world and can do things that are impossible and terrifying.
The appearance of the clown is often a very scary element. Their exaggerated makeup, big smiles, and colorful yet often tattered costumes can be quite unnerving. For example, in 'It', Pennywise's white face with red lips and yellow eyes is terrifying.
The ghosts are often really scary. Like the white lady, her pale appearance and sudden appearance in the middle of the night can send shivers down your spine. Also, the idea of being haunted by the spirits of the dead in places like old houses or lonely roads is very frightening.