When I was young I used to stay at my grandparents house, they had a walk-in attic which I was absolutely petrified of ... and of course I had to sleep in the room just past the walk-in attic. The house was out in the countryside, it was so quiet you could always hear if anyone else was still up.
I used to have real trouble getting to sleep and would often wake up in the middle of the night afraid to move so I would just lie still. Anyway one night about 3:00-4:00 A.M. I woke up and I was feeling brave, I was going to get over this stupid fear of the dark... so I whispered under my breath "If anything is there please tell me" almost instantly there was two large knocks on my bedroom door. I never asked again.