How about 'Knock, no one there.' You hear a knock at the door, but when you open it, there's nobody. It leaves you with a sense of unease and the feeling that something is playing tricks on you.
Here are some: 'Alone in the dark.' It gives a sense of isolation and the unknown in the darkness which is quite terrifying. Another one could be 'Footsteps, no one there.' Just the idea of hearing footsteps but seeing no one is really spooky. And 'Lost in the forest' also works. Being lost in a vast and often unpredictable forest is a nightmare scenario.
Just focus on fear. For example, think about things that scare you like a haunted house, and then sum it up in five words like 'Haunted house, no escape.'
Think of a simple fear. For example, 'fear of being alone'. Then turn it into a five - word story like 'Alone with the echoes.' Another way is to consider spooky settings. If you think of a cemetery, you can make 'Cemetery gate won't close.' Also, use sudden actions or events like 'Knife in the darkness.'
I'll start with this one: 'Midnight knock, no one there.' It gives that immediate sense of unease. You're in a quiet house, it's midnight, and suddenly there's a knock on the door. But when you open it, there's no one. It plays on our natural fear of the unknown in the dark.
Footsteps in the attic. Alone in the house, hearing those footsteps in the attic is really terrifying. You don't know what's up there, and every step seems to be getting closer, sending shivers down your spine.