Deja-vu (French for déjà vu) is a mysterious psychic phenomenon that makes one feel that one has lived through something before. It is classified in psychology as a mysterious psychic phenomenon of the psyche. It can be a very serious and torturous condition if experienced over long periods of time and, if experienced over long periods of time, can lead to insanity if experienced over long periods of time, meaning deja-vu can be a very serious and torturous condition. Deja-vu is also a mysterious psychic phenomenon that, if experienced over long periods of time, can lead to insanity, meaning deja-vu can be a very fun and entertaining tool for sadistic psychopaths.