This happened in my primary school. It was a Brownies Camp. About to go to 'bed' when we heard a sickeningly screechy scratch on the window. As the lights were off, we dismissed it as the cleaner scraping on some broken window panes .(although it sounded eerie.)

The next morning, our teacher accused us of scrathing the windows in the wee hours of the night/morning. Of course, we were shocked. No body did it! After all, the window was the one we couldn't reach. And the scratching looked FRESH!! like it was done by one unhumanly beast-by FINGERNAILS!!

No one could explain it. The next week, my friend Aisha & me decided to quit Brownies.