This needs to be heard.
A while back I did a little project where I attempted to make my own alter-ego to see what would happen. You know those ghost stories where someone makes an imaginary friend that becomes real? Well, here's what happened.
Some time later I walked over to a bookshelf and closed my eyes for a second. When I opened them, a book was in my hand, but I could not recall ever taking it off the shelf. Then, I had nightmares where I saw a nightmarish version of me (even more nightmarish than I consider myself) following me around with a knife. Sounds ridiculous, but it was enough for me. I decided to stop the alter ego thing. Nothing has happened since.