If you have ever woken up in the middle of the night and found you can’t move, or even cry for help, you have experienced sleep paralysis. If, during this bizarre paralysis, you suddenly felt that someone—or something—was watching you, you have come face to face with the waking hallucination known as the Intruder.

Check this out!

#5 sucks, poor rats.. But the others are pretty interesting

http://www.cracked.com/article_17476_7-man-made-substances-that-laugh-in...