Here's a fun little page dedicated to micro horror stories. Each story is only two sentences long.
Here are a couple of Alone at Night's Favorites:
"I begin tucking him into bed and he tells me, 'Daddy, check for monsters under my bed.' I look underneath, to amuse him, and see him, another him, under the bed, starring back at me quivering and he whispers 'Daddy, there's a monster in my bed.'"
"There was a picture in my phone of me sleeping. I live alone."
Go to the page to read the rest.