Holy shit. I had completely forgotten about this book.

Actually I still can’t remember it because I was young when I read it, but I def remember the artwork.

This happened in my game. I spoke with the player about having his character swapped with another version of him from an alternate universe, and he was down for it. Then it happened in game. None of the players realized it. This went on for years (literal real time years) before he betrayed them. It was delicious.