Before I begin my story I would like you to know that this is one of my first ghostly encounters I have experienced. It was nothing too big but up to this day I find it extremely creepy.
It was an ordinary day at school, kind of rainy. No one goes to the bathroom during class time - the bathrooms are on the opposite side of the classroom and close to the field so it's far away from other people. It has no windows, just one small light. If you closed the iron door and turned off the lights it would be pitch black, as the bathrooms have another room around it (a room used to store props for school plays and such).
I had to go to the bathroom to do the usual stuff. I went alone as always - I wasn't afraid of being alone. I started humming to myself to make it seem like I wasn't so alone. As soon as I got off the pot I, still standing in the stall, heard the heavy iron door THUMP shut. I left the stall and walked over to the door. I opened it or at least TRIED to. It was locked. (Luckily from the inside, not the outside other wise I'd be trapped) But the weird thing is, is that it's one of those doors here you have to twist the lock 180 degrees with a big effort in order to lock it, and it must be closed before it can lock otherwise the lock will just bump against the door frame when you close the door. But of course I took no notice at the time.
Up to this day I find it very strange and the more I think about it the stranger it seems. I no longer go to that school, but my house is only 5 minutes away. I can even hear the bell ring from my driveway.