Cousin's Doppleganger

This morning our cousin that has been staying with us came downstairs and ask me about macaroni salad that we had in the fridge and i told him to go ahead and eat it. He got it on a plate and then went back upstairs, ate and then brought the plate back down. I seen him doing this and seen him come back in through the playroom,look at me, as usual, because I was sitting on couch and went back upstairs and went back into the bedroom and shut the door, I heard it shutting because the door is messed up and it almost sounds like they slam it to shut it, but don't. We were sitting in the livingroom and our dog started barking and we wondered what he was barking at. Karen got up and went to look and it was our cousin coming back from being over town. He said he left after he brought his plate back down and I told him what happened and how I thought he was in the bedroom. Whatever went to the bedroom looked exactly like him and walked like him.Remember, this happened daylight, not night, so starting to wonder what the change of the house feeling is.