The unpredictability. You don't know what the stalker will do next. They could go from just observing to actually harming you at any moment. For example, in some stories, the stalker suddenly breaks into the victim's house. It's that sudden escalation that is really terrifying.
The constant feeling of being watched in these stories is terrifying. Just like in the story where a person could sense someone's eyes on them all the time, whether at home or out in public.
The unpredictability of the stalker's actions. They might seem harmless at first, but then escalate to really dangerous behavior like breaking into your home or physically attacking you. For example, in some stories, the stalker starts by just leaving gifts at the victim's doorstep, but then it turns into something much more menacing. Another aspect is the invasion of personal space. They might get too close in public places or follow you everywhere you go, which is extremely unsettling.
The feeling of being constantly watched. In many stalker stories, the victims just can't escape that sense of eyes on them all the time. It's like their privacy is being invaded in the worst way.
One story I heard was about a girl who noticed the same man everywhere she went - at the grocery store, near her work, and even outside her apartment. He would always stare at her intently. One day, she found a strange note in her mailbox with details about her daily routine. It was so creepy.
One of the scariest stalker stories is about a woman who noticed the same man following her everywhere she went. He would show up at her work, her gym, and even outside her home. It got so bad that she had to change her daily routine completely. Another story is of a man who received anonymous letters filled with details about his life that only someone constantly watching him could know.
The unknown is the most terrifying. For example, not knowing what is making that strange noise in the dark. It could be anything from a wild beast to something supernatural.
The unknown is a really terrifying element. For example, in many stories, there are strange noises in the dark that you can't identify. It could be a wild animal, but your mind imagines all sorts of supernatural things. Another is isolation. When the characters are alone in a spooky place like an old cabin in the woods or an abandoned building, it makes the situation scarier because there's no one to turn to for help.
The unknown is a really terrifying element. For example, in a sleepover story, when you hear strange noises but don't know what's making them. It could be anything from a ghost to a wild animal. It plays on our fear of the unexpected.
The sense of being constantly watched is one of the scariest elements. Just knowing that someone is out there observing your every move without your permission gives you the chills.
The sense of being watched. In the forest story, the hikers feeling like the trees were alive and watching them added a lot of terror. Also, in the doll story, the girl feeling like the doll was somehow aware and watching her even at night was terrifying.