Incorporate elements of mystery. Don't reveal everything at once. Drop hints throughout the story about what might be causing the scary events. Is it a vengeful spirit? A cursed object? Let the readers try to piece it together as they read. And use sound effects or ambient noises if it's an audio - based story. The howling wind outside or the dripping of water in a dank basement can really enhance the scariness factor.
There's the story of 'The Vanishing Friend'. During a sleepover, the reader and friends are chatting and having fun. Suddenly, one of their friends disappears without a trace. They search the whole house - under the beds, in the closets. As they continue to look, they start to notice that things are moving on their own. Pictures on the wall turn upside down, and doors open and close by themselves. Then, they find a note written in what seems like blood that says 'You're next'.
The unknown is a big factor. When strange things happen during a sleepover like unexplained noises or objects moving on their own, it's terrifying because you don't know what's causing it.
One of the best sleepover scary stories is 'The Red Room'. It's about a person who decides to spend the night in a supposedly haunted red room. As the night falls, strange noises start to come from the corners of the room. The temperature drops suddenly, and the person feels an unseen presence. Shadows seem to move on their own, and every time they try to look directly at the source of the movement, there's nothing there. It builds up a great sense of dread and mystery.
One appropriate scary story could be 'The Haunted Doll'. It's about a doll that moves on its own at night. A girl named Emily found an old doll in the attic. Every night, she would hear strange noises coming from the doll's room. When she checked, the doll was in different positions each time. It was really creepy but not too extreme for a sleepover.
One story is about a girl who heard strange scratching noises on the window at her sleepover. Every time she looked, there was nothing there. But the scratching got louder and closer. Eventually, she saw a pair of red eyes in the darkness outside. She was so terrified that she hid under the covers until morning. When she told her friends in the morning, they just thought she had a bad dream.
You can use a really quiet and suspenseful voice when telling the story. For example, when you get to the scariest part, slow down your speech and lower your voice to a whisper. This can make the listeners feel more on edge.
One scary sleepover story could be about a haunted doll. A group of friends at a sleepover found an old doll in the attic. During the night, they heard strange giggling coming from the doll. When they looked at it, its eyes seemed to follow them around the room. They were so scared that they locked the doll in a closet, but the giggling continued until morning.
Here's another. At a sleepover in a cabin in the woods, the friends heard strange scratching noises on the window all night. One brave friend peeked outside and saw a pair of red eyes staring back at him. He quickly pulled back the curtain. Then they heard something climbing on the roof. They huddled together in fear until morning, not knowing what was outside trying to get in.
Tell interactive stories where the sisters can choose different paths for the characters. For example, when the main character comes to a fork in the road, the sisters can decide whether she goes left or right, and the story unfolds accordingly. This makes them more engaged.
One not - really - scary ghost story could be about a friendly ghost who just wants to play music. He haunts an old music store and at night, he plays the piano softly. People who pass by the store sometimes hear the music and think it's a CD playing, but it's actually the ghost.