It might be the sense of isolation the kids feel. When the babysitter cuts off their communication with their parents, it creates a really scary and helpless situation for the kids. They are alone with someone who is starting to act very strangely, and they have no way to get help.
The sudden appearance of something strange. In the story of the face at the window, the babysitter is just going about her job, and then suddenly there's this creepy face. There's no warning, and it's something that seems out of place and threatening, which is really terrifying.
The sudden and unexplained noises are really scary. For example, in many stories, there are strange creaking sounds or thuds that make the babysitter jump. It creates a sense of unease right away.
The scariest part could be when Claire first hears the unexplained noises. It's always terrifying to be in a house and hear strange sounds with no obvious source.
Well, the contrast between the expected role of a babysitter (someone who is supposed to be caring and safe) and the appearance and behavior of a clown can be extremely scary. A clown is often associated with the circus, a place of entertainment, but when it's in a babysitting role, it's out of place. And if the clown - babysitter has some sort of 'evil' or 'creepy' backstory that is hinted at during the story, that can be really terrifying. For example, if there are rumors that the clown has been involved in strange disappearances in the past while babysitting, that would make the whole situation much scarier.
The scariest parts are often when Sarah is alone and helpless. Like when she's trapped in a spooky place with no way out. For instance, if she's locked in a haunted attic and she hears strange noises all around her, feeling completely alone and vulnerable makes it very scary.
The scariest part in a Kimberly scary story could be the sense of isolation. For example, if Kimberly is in a spooky place all alone, like an empty attic, and she hears strange noises. She has no one to turn to for help, and that feeling of being completely alone in a scary situation is terrifying.
In a scary dora story, the isolation and being trapped in a spooky place are really scary. For example, when Dora was locked in the haunted house and couldn't get out. She was alone with all those creepy things and didn't know what to do.
The scariest part is often when the raccoon shows abnormal behavior. For example, if it stares directly at a person with an aggressive look, like it's not afraid at all. It gives a feeling that the raccoon has some sort of malicious intent.
The sudden transformation of the cute and innocent - looking Barbie into something terrifying is very scary. For example, when its eyes change color or it starts to move in an unnatural way.
The sudden cut - off of the call can be really scary. Just like in the story where the woman calling about an intruder had her call end abruptly. It leaves so much mystery and makes you wonder what happened to the caller right away.