What makes a spooky kid story so effective?
The unknown. When you don't know what's going to happen or what the spooky thing is, it scares you. For example, in a spooky kid story, a shadow that moves but you can't see what's causing it. It plays on your fear of the unknown.
The vulnerability of the kids in the story. Kids are small and not as powerful as adults. So when something spooky happens to them, like in a story where a kid is alone in a big, dark house and strange things start to occur, it makes the reader feel more scared for them. Also, using familiar settings like a bedroom or a schoolyard and then making them spooky is very effective. For instance, a normal schoolyard that at night has strange noises and figures. It twists the perception of a safe place into a terrifying one. Another important factor is the use of suspense. Building up the tension slowly, like a kid hearing a soft noise at first and then it gets louder and louder, keeps the reader on the edge of their seat.
A spooky kid story is effective mainly because it often taps into our primal fears. Childhood is supposed to be a time of innocence, so when something dark and scary enters that world, it's jarring. For example, a spooky story about a kid's teddy bear coming to life in a menacing way. We expect teddy bears to be sources of comfort, but when they become sources of fear, it really gets to us. Also, the use of sound and atmosphere in the story is crucial. If the story describes a spooky, creaking floorboard or a howling wind outside a kid's window, it creates a vivid and scary image in our minds. And the fact that kids in these stories are often isolated, either physically or emotionally, adds to the sense of dread. They don't have many resources to deal with the spooky things, which makes the situation seem more dire.