oys... it doesnot matter if you would like to tell it a supernatural conotation or encounters with unexplainable things. My whole point is, even if the article posted here implies chemical imbalance in the brain or hyper active brain which responds to the faint electrical signals for such phenomenon to occur, once you are grown up with that deep embeeded fear that has been injected in you( as elders tell you their story eventhough they are a product of their fiction or sometomes true, or horror movies) you tend to see devil even in the dark clouds.... i agree with you in the mass hysteria part but i would like to term it supernatural only because those things are not explainable by nature or science that we have the knowlledge right now..Ofcourse there is school of thought that says its only mental problem but when you feel it by yourself then you have to think and realise that there is something beyond our perception!!!