Well, start with a scary setting or a mysterious character. Like, 'The old house creaked. A shadow moved behind the curtains.' Make it short and spine-chilling. Also, use simple but powerful words to build tension quickly.
You can play with common fears. Say, 'I heard footsteps in the attic. When I opened the door, no one was there.' Keep it simple, yet leave the reader imagining what could happen next.
Think of a common fear and describe it in an unusual way. Say, 'The mirror showed my reflection. But it wasn't mine.' Keep it short and intense.
The little girl found a doll in the forest. As she picked it up, the doll's eyes started to bleed.
Think of a common, ordinary situation first. For example, 'I was walking my dog at night.' Then add a terrifying twist like 'Suddenly, the dog started growling at me, and I realized there was something following us that only the dog could sense.'
One way is to set a spooky scene in the first sentence, like 'The graveyard was covered in fog at midnight.' Then, introduce a terrifying element in the second, such as 'Out of the fog, a pale hand reached for me.'
The phone rang at midnight. When I answered, all I heard was heavy breathing and then a whisper of my name from an unknown voice.
The moon was full. But the werewolf outside my window wasn't howling at it, but rather staring right at me.
Well, it's about the unexpected. In a 'two sentence horror story' like 'I heard a knock at the door. When I opened it, there was nothing but darkness.' The suddenness and the unknown in just two sentences can send shivers down your spine.
Well, you could think of a common fear and build on it. Like, 'I heard footsteps in the attic. When I went to check, the door slammed shut behind me.' The key is to create a sense of dread quickly.
First, come up with a terrifying idea. Then, in the first sentence, set the stage and hint at the horror. In the second sentence, reveal the full horror in a sudden and unexpected way.
Sarah walked down the dark alley. Out of the darkness, a pair of glowing eyes stared at her, and she knew she was being hunted.