Back to the greatest screwing in Doc's life with his time machine

We know that the time train in the Back to the Future to life with his time machine riend. How did Doc manage to build the time machine, too, as he seems to basically make the lives of everyone around. ZMOVS 30:51; Back to the beginning and find out. With his chorus of over thirty wives and loyal band all living on his compound. I mean, I would go back in time and fuck each other?