Once, me and my family where visiting some relatives. They live in a quite big flat but it still lacked enough beds so me and my brother had to share one in my cousins old room when it was time to sleep. In the middle of the night, i awoke only to find someone entering the room with a flashlight. I didn't say a word, just pretended to sleep as the person with flashlight searched around in a closet that stood next to the bed. Suddenly, the person with flashlight left and everything was back to normal.
Thinking back to it, it might have been my cousin trying to get some stuff from his closet without wanting to accidentally waking us up, it was pretty scary when i excperienced it though.
