This story isn't all that scary but it is pretty interesting.
When I was younger (around 9 or 10), I was very close to my next door neighbor, Mr. Mills.
Unfortunately, he died of a heart attack around that time.
One night, I woke up from a deep sleep because of a strange feeling I had. I looked at my doorway and saw a dark figure standing there, facing my direction. It was dark, so I couldn't completely make out every detail of the figure, but it looked like a man wearing a flannel shirt and a baseball cap (the same type of clothing Mr. Mills normally wore). I assumed that my parents probably just had some clothes or something hanging over their door that looked like a man because of the darkness (their bedroom was across the hallway from my room), so I shrugged off the figure and went back to sleep.
The next morning I asked my parents if they had anything hanging over their door or if there was anything in the hall and their answer was negative.
For the next few days, strange things happened: lights flickering, the shower turning on and off, and the dogs barking at the hallway. All of the strange things stopped after the next couple of weeks, but I think it was just Mr. Mills checking on me.