This story actually happened to my late mother when I was visiting her in the Philippines one summer. The story goes like this...
So I went to the Philippines to spend my summer there. I got invited to a house party and ended up spending the night over. I came home around 8 or 9ish in the morning and went straight to my bedroom to sleep some more. I saw my mom cleaning fish in the kitchen and said hi to her and that I am going to sleep some more.
About an hour later she said she saw me on her peripheral sight go out of my room and went straight to the living room and turn the TV on. She then called for me because she needed something from the store and asked me if I could get it for her. Of course no one answered. She then called my name again, and again no one answered. After the second attempt she went to the living room to ask me why I was ignoring her call to find no one there. And you know the creepy part, the TV was on.
She then went to my room and woke me up. She asked me if I was just in the living room and of course I said no. I told her I've been sleeping the whole entire time. She thought I was kidding because she said she swear she saw me getting out of my room to the living room and turned the TV on. I told her I don't think watching TV will help with my hangover and if I got up, I would probably go to the kitchen to get water instead of watching TV. That left a confused look to my mom's face and up to this date I could never explain what happened.
Just a question though, what is a doppelganger? Is it a ghost/spirit? Is it a demon?