The magic machine is an interesting idea. I tried looking into a mirror and closing my eyes and then opening them again to change my self image, but sure enough I opened my real eyes. In the heat of the moment I'd forgotten not to do that. As for "jumping" into somebody causing all kinds of problems, I could see that happening, but I also figured that if you'd created this person by having them walk around the corner, you could create them to be a shell of a dream character with no personality or free will I suppose, a blank minded person you can just take control of. I wouldn't try doing it to a dream character with a personality and believable characteristics, it's much too difficult to do anyway.