Do you believe in DOPPELGANGER?

A doppelganger is the ghostly double of a living person. The word doppelgänger is adapted from German doppel, meaning "double", and gänger, translated as "goer". The term has, in the vernacular, come to refer to any double or look-alike of a person, most commonly in reference to a so-called evil twin, or to bilocation.
Alternatively, the word is used to describe a phenomenon where you catch your own image out of the corner of your eye. In some mythologies, seeing one's own doppelgänger is an omen of death. A doppelgänger seen by friends or relatives of a person may sometimes bring bad luck, or indicate an approaching illness or health problem.The doppelgängers of folklore cast no shadow, and have no reflection in a mirror or in water. They are supposed to provide advice to the person they shadow, but this advice can be misleading or malicious. They can also, in rare instances, plant ideas in their victim's mind or appear before friends and relatives, causing confusion.
Source:wikipedia
I learnt the word from Saiyuki Reload 2. ok, it's a comic. But doppelgangers are so scarrrry!!!! I mean, what if one day you see the other YOU?! Scary? yes no? Ahhhh!