I find 'The photo on the wall changed. My dead grandmother was now smiling.' quite disturbing. It combines the normalcy of a photo on the wall with the unexpected and eerie change. A photo is supposed to be a static memory, but when it changes in such a strange way, it makes you feel like there are forces at work that we can't understand.
One common element is the presence of the unknown. For example, in many kyutie horror stories, there are things that the characters can't explain, like strange noises or objects moving on their own. Another element is a sense of isolation. This could be a person alone in a big, old house or a group of people cut off from the outside world in a remote location. Also, there's often a spooky or eerie setting, such as a haunted forest or an abandoned building. These elements work together to create a feeling of fear and unease in the reader or listener.
One kyutie scary story could be about a haunted doll. The doll seems cute at first but at night it starts to move on its own and whispers strange things. It terrifies the family that owns it.
Well, one might be about a haunted house where strange noises come from the attic at midnight. Every time someone tries to go up there, they feel a cold hand on their shoulder.
Two-sentence horror stories can be quite scary. They often use simplicity and ambiguity to let your imagination run wild, which can make the fear more intense.