Think about emotions. For instance, 'The young woman received a letter. Her face lit up with joy as she read the good news.' By including an emotion, it makes the story more relatable and engaging even though it's only two sentences long.
Another really scary one could be 'My phone rang at 3 am. The caller ID said it was me.' It plays on the idea of the self being something other or unknown, and calls at that time are always spooky.
The first sentence of the Long March of the Seven Laws was,"Go a thousand miles and never return." I've been loyal to my country all my life. It described the historical significance and theme of the Red Army's Long March.
I think 'The clock stopped at midnight. Then I heard footsteps.' is quite scary. It gives this feeling of something ominous starting right at a spooky time.
One characteristic is that they can be very detailed. For example, they might describe a complex sequence of events all in one sentence, like a character's entire journey from start to finish. They also often have a clear beginning, middle, and end within that single sentence.