The feeling of being trapped. Once you've let the hitchhiker into your car, it's not that easy to get them out, especially if they don't want to leave. And if they turn out to be dangerous, you're in a very vulnerable position in a small, enclosed space like a car.
The sudden appearance of anacondas is often the most terrifying part. Just like in the story of the fisherman, when the anaconda emerged from the water unexpectedly. It gives no warning and can be right in front of you in an instant.
The most terrifying part is often the power of the acid to quickly and destructively dissolve things. Just the thought of a substance that can eat through metal or flesh in a matter of seconds is really scary.
In many scary rescue stories, the time pressure is terrifying. For example, in a rescue from a sinking car. The water is rising fast, and the rescuers have only a short time to break the window and get the people out. Every second counts, and the fear of not making it in time is huge.
The fact that skeletons are often associated with death and the afterlife makes them terrifying. In many stories, they carry a sense of doom. They might be the remains of someone who died horribly, and their appearance can be a sign of something bad about to happen. For instance, if a skeleton shows up in a person's dream in these stories, it usually means that death is near. Also, the way they move in some stories, like their jerky, rattling movements, is really spooky.
The feeling of vulnerability. When an intruder is in your home, your safe space is violated. In many stories, the victims are often alone or outnumbered, like a single mother with young children facing an intruder. It's terrifying because they might not be able to protect themselves fully.
I think the unknown is the most terrifying part in these stories. When something strange happens like unexplained noises or apparitions (even if it's just a false alarm), it really gets to people. There was a story where a strange knocking sound came from the cargo hold and no one knew what it was. The passengers were all very frightened as the crew tried to figure out the source.
The isolation is often terrifying. Like when Caillou is trapped in the abandoned house, he's all alone with no one to help. That feeling of being on your own in a scary situation is really frightening.
Strange and unexplained phenomena are also very scary. For example, seeing unknown objects on sonar or experiencing forces that seem to be pulling the submarine. In the story where the object was erratically moving and pulling the sub towards it, not knowing what it is or what it can do creates a great sense of fear. There's also the fear of the unknown depths of the ocean and what might be lurking there.
The unknown and the sense of impending doom. In the story with the truck driver and the strange noises and the apparition, the hitchhiker had no idea what was going to happen next. The fear of the unknown, like whether the driver was a threat or if there were really ghosts, is a very scary aspect in these types of stories.
Well, when strange things start to happen to the children they are babysitting. Like if the kids start acting really odd, as if they are possessed or something. It makes the babysitter feel helpless because they don't know what's wrong and how to fix it. Also, seeing apparitions or strange figures, especially when they seem to be menacing, is extremely terrifying.