There's a new movie out called Jonathan. Here's the Redbox info: https://www.redbox.com/movies/jonathan Two brothers share the same body, they each have 12 hours of control. Dang it - I had this same idea I was going to put into a book - call it "Doppelganger" after the german word for "double" with a connotation of some kind of wraith or ghost. These two personalities wouldn't know about each other - the guy would go to bed, and as soon as he fell asleep, the other would wake and lead a different life. Of course, "Government experimentation" is what caused all this, and there was to be some kind of reveal (of course, with a woman involved) and these two would gradually suspect that his girl was seeing someone else, and slowly find out about the other, and then to find out that the 'other' is himself. Some kind of weird and explosive climax had to occur where he exposed everything or freed the other experimentees or something. So my idea was a bit different, but the same basic idea. Well, so much for that. I probably wouldn't be that great of a science fiction writer anyway, and it would be years before I had any time to get around to it. Still, I think it would have been pretty good!