Merriam-Webster defines doppelganger as: "The ghostly counterpart of a living person." They are supposed to be bad omens, evil twins, or portends of death.

Anyway, has anyone here ever seen one? Also was it a negative thing and are there any alternative theories regarding them?

So here is my story:
When I was 5 or 6 my family lived in an old Victorian two-story row house. It was long and narrow in design with a store located on the first floor. I was playing in the hallway which connected the living room to the kitchen. This hallway was the only way to access the kitchen at the back of the house and we were on the second floor. I saw my mother walk across the kitchen doorway and heard her moving around in the kitchen. Then my mother called for me from the living room. I jumped up and ran into the kitchen but it was empty. I went back down the hallway and she was sitting in the living room. I told her I just saw her in the kitchen, but she denied being in there. It was really weird. I only heard of doppelgangers a few years ago, but it seemed to explain this incident. There was nothing apparition-like about her appearance and I don't remember anything bad or evil occurring afterwards.

Actually in the paranormal world, Doppelganger is correct without the umlaut above the a. The definition is correct too. I've heard of doppelgangers, but never experienced it, or know of anyone else whose experienced it. It's not my area of expertise. I did however find an interesting article about them. I hope someone else can help you, Rowan.

In the meantime, here's the article I found:
http://paranormal.about.com/library/weekly/aa111102a.htm

I have never experienced one, nor have I heard of anyone experiencing one.