Her appearance is one factor. Maybe she has a pale face, or strange eyes that seem to look right through people. Also, her behavior like not blinking or staring constantly at passengers is really creepy.
The fact that she is so out of place on the train. She doesn't seem to belong there, yet she is there among the normal passengers. Her actions, like whispering things that no one can understand and disappearing suddenly, all contribute to making her extremely frightening. It's like she represents the unknown and the things that go bump in the night, and that scares people on the train.
Well, it's a combination of things. Her unearthly silence for starters. She doesn't interact like a normal person. Then there are the strange occurrences that seem to happen around her, like the lights flickering. It gives the impression that she has some sort of otherworldly power or is associated with something supernatural, which is quite frightening.
The mystery around the character of Momo makes it scary. We don't really know who she is or what she truly wants. Her appearance, often described as having long hair covering her face, is a classic horror trope that gives an air of the unknown and unease.
The unknown and the sense of isolation. The girl is often alone on the train, which is a confined space. This makes any strange occurrence more intense as she has limited options to escape. For example, if she sees something scary outside the window or inside the train, she can't just run away easily.
Her presence in strange and often lonely places. The red scarf just enhances the overall eerie effect. For example, if she's seen in an abandoned building or a desolate forest, the red scarf is like a flag that catches your attention and then you notice her strange behavior or appearance. It gives off an air of danger and the unknown.
Her appearance is often strange. Maybe it's the red scarf that stands out in the dark, making her seem like an otherworldly figure.
The unknown. In a scary story, not knowing what's going to happen next or what the strange thing really is makes it scary. For instance, if there's a noise in the attic, but you don't know if it's a ghost or just a rat, the mystery creates fear.
The unknown. When there are elements in a story that are not fully explained or understood, it makes it scarier. For example, in a haunted house story, if there are strange noises but no clear source, it gives the reader or listener's imagination a lot to work with. Our minds tend to create the scariest scenarios when there's a lack of information.
The atmosphere in a snarled scary story is crucial. If it's set in a snarled, desolate place like an old, abandoned mansion or a dark forest with snarled trees, it immediately gives a sense of dread. Also, the use of snarled characters or creatures, like a snarled monster with sharp claws and a menacing look, can send shivers down our spines. The descriptions of their snarled features and their snarled actions, like a sudden snarled lunge towards the protagonist, are what make it truly frightening.
The mystery behind what's on the other side of the keyhole can be very frightening. You can't see the whole picture, just a limited view, which makes your imagination run wild.
The unknown. In a personal scary story, often it's the things we can't see or understand that are the scariest. Like in my attic story, not knowing what was making that noise.
The unknown aspect of his life. We don't know his past, why he behaves the way he does. Maybe he has a dark secret or has been through some traumatic event that has made him this way. And not knowing this makes our imagination run wild, creating all kinds of terrifying scenarios in our minds about him.