An Owl
When I was a kid, my mother, sister and I ended up in a hotel in greece that was under construction.
During the night, an owl somehow got into the bathroom (through an open air vent or something).
We woke up to a huge racket coming from inside the bathroom, things crashing to the floor etc... we were terrified!
Eventually, it dawned on us to open the room door and then throw the bathroom door open and run...
Eventually, the bird headed for the outdoors.
I remember being pretty surprised at how big it was, up close.
-R