This is something that happened in 2012 in my home in Seattle, Washington. I was sitting in my bed reading a book about urban legends and myths, which has been an obsession of mine for quite a while.
I was just sitting there, already paranoid from reading about creatures that would likely break into my home and kill me and everyone else in the house, when I felt like I was being watched. I looked around and didn't see anything, so I figured it was just the paranoia.
I went back to my book for about ten minutes, then heard something slam into my window. This scared the crap out of me. It wasn't something I could just ignore, so I looked up just in time to see a strange gray figure run off into the darkness. I looked at my window, and there was an imprint of its face on it, probably due to the fact that its face was wet.
It was horrible. Slightly human, yet more like a beast than anything else. It had a large lower jaw, and either had six eyes or just some random dents in its skull. I didn't know what this creature was, and monsters are something I have studied since the age of six (I am 14 now). My best guess is it was an alien creature, and something that had never been recorded in any myths or legends before.