They're popular because they give a bit of a thrill without being too terrifying. People like the idea of a little scare that ends up being okay in the end.
One story could be about a friendly ghost that just wants to help a little girl find her lost doll. It's not really scary because the ghost has kind intentions.
The element of truth in these stories makes them scary. When we know that something really happened, it becomes more terrifying. For example, if a story is about a real murder case with some unexplained aspects, like the killer was never found or there were strange circumstances around the crime. It makes us feel that such danger could be lurking around us too.
The fear of the supernatural that these stories play on is what makes them so scary. Since we live in a world where the natural laws seem to govern everything, the idea of a goast that defies these laws is deeply unsettling. It challenges our understanding of reality and makes us feel vulnerable.
Alligators are unpredictable. In stories, they can be lurking quietly in the water or the mud, and suddenly lunge at their prey without warning. Also, their powerful jaws are a big part of what makes them scary. Once they clamp down on something, it's very difficult for their prey to escape.
The unknown elements in Denis scary stories are likely to be very scary. Our minds tend to fill in the blanks with the scariest things we can imagine when we're not given all the details. Also, the atmosphere created, like a gloomy setting or a sense of isolation, can heighten the scariness. If the story is set in a deserted place where no one can hear the characters scream, it adds to the fear factor.
The use of atmosphere. For example, in many stories, it's often a dark and isolated setting like an old abandoned house or a desolate forest. This immediately makes the reader feel uneasy.
The scariness in the '5 seriously scary stories' might come from various factors. It could be the atmosphere created. If the stories are set in a dark, desolate place like an abandoned asylum or a fog - covered forest, that can be really spooky. Also, the characters' helplessness in the face of the horror can add to the scariness. For instance, if they are trapped in a situation with no way out and something terrifying is approaching them.