In the abandoned house, I found a diary. The last entry said 'They're here'. Then I heard scratching at the door.
I opened the closet. Red eyes stared back. I slammed it shut. But the eyes are now under my bed, waiting for the dark.
Walking through the forest, a mist surrounded me. Voices whispered my name. I ran, but the voices were inside my head.
Think of a simple, creepy situation like 'Lights out. Something moves. Shadows.'
Use simple but spooky words. For example, 'Footsteps, but no one'. The words 'footsteps' immediately create a sense of someone or something being there. But when you add 'but no one', it becomes a horror story in just five words. It makes the reader wonder what is making those footsteps if there's no one there.
Use strong imagery. For example, 'Blood on white sheet'. Pick words that evoke fear like 'dark', 'death', 'lost'.
Just think of a sudden, dark twist. For example, 'He walked. The shadow had no feet.'
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.'
The moonlit night, a secret meeting.
Think of a character and an action. Such as 'Boy laughed, toy broke'. Here we have a boy as the character, laughing as the first action and then the toy breaking as the second action which creates a very brief story in just four words.