"Because..." says a voice that sounds remarkably like yours, except more evil.
You spin around to see another you standing right behind you.
"Because there's only room for one Brad in this dimension."
You take a defensive step backward, but it's too late. You pounce on you.
You take a few blows, but you're able to kick you off of you for a moment.
And then you see you reach into the back of your underpants and pull out a medieval battle axe.
You shit a brick.