Housebroken Lunatic said:
I'd kill it.
Sure, it might possess a dirty imagination of equal grade to my own, as well as being a rather unselfish lover. But it would also possess the flawless methods of argumentation and discussion that I do, meaning that it would be impossible for me to win any debates, and also there's that issue with not being completely unique anymore.
Still it would be one vicious fighter if it has to fend for it's own life. It would use every dirty trick in the book and would probably start swinging a knife at me too. So it would be a challenge, but a necessary one.
There is a theory which applies to this actually- if your first thought upon seeing your clone is "kill it", so would it's initial thought. Your reaction time would be the same, your speed, your fighting style... every time you feint, your clone would know it was a feint, because that would be what they'd do in that situation. The fight ends when one of you has an extra bit of luck, which will be shortly followed by the other fighter getting the same luck, and you both crash to the floor in a pool of your own intestines.