This happened to me too. Last year. I remember asking about it on GLP and people responded that it was a "shadow person". Lots of info about it on google.

For me, I woke up and couldn't move for a few seconds. I saw a black humanoid figure in my room with no features. When it noticed that I saw him (it?), it jumped out of the window.

I still have the image in my head. Very creepy.