I was at a mates house spending the night when I was in middle school.
As expected we'd stay up to all hours, which didn't matter most of the time except the bathroom was right near his parent's room. About the only time we'd get in trouble was when someone would wake them up when nature called. To avoid this we'd go out the basement door and just pee in the woods.
The door stayed unlocked most of the time because we'd managed to lock ourselves out more than once. This was also compounded by the fact that we'd all wander out and find something to do in the woods on a regular basis.
This night his older brother was home and kept barging in the basement door and reigning chaos from above, so we decided to lock the door just to deter him. Not that it really would have kept him out, but at least he'd have to use the key and that took 'barging in' fun out of it.
About midnight we heard the handle jiggling and didn't think much of it, figuring it was his brother. After about 5 minutes of off and on handle fondling (my vocabulary has decided to not function at a high level today) we finally hit the door and yelled for him to stop.
No response no more clattering of the handle. Great, we can move on right?
Well about 10 minutes later it started again, and the process repeated.
This went on for about 2 hours, until finally after telling him to stop we just said screw it and ignored it.
He continued for about 30 minutes after our last attempt for him to stop and then just gave up.
Well fast forward to about 9am, we were just stirring and one of my mates had to go to the bathroom. If you've ever had a sleepover like that, there are bodies strewn wherever there is space and once the first person starts walking around it kind of stirs the nest.
We all started stretching and making our way to relieve ourselves of all the soda we'd binged on the night before. As I go walk outside I grab the door handle to close it behind me and noticed it felt rough.
After looking at it I saw that the space around the keyhole was all but destroyed. There were giant scratch marks on every surface and the metal guides were bent and skewed. I asked my friend that lived there what had happened, and he said it was the first he'd noticed it.
Not really wanting to get blamed for something his brother did, we went upstairs and told his parents about the night before.
After his Dad went down to see what we were talking about, he went completely white and ran upstairs to call the cops.
Evidently someone had been trying to force the lock open while we were all inside. That's actually happened to me more than once on different occasions, what completely freaks me out about this time was that this person knew we were in there and that we knew someone was trying to get in. Even so he REPEATEDLY tried to force his way inside.
God knows what sort of person that was.