Time Travel Movie - Bad guy has traveled back in time to fuck up future events and make himself King President Ruler of the Solar System or whatever. Because bad guys like to time travel, that's why. They'll use any excuse possible. Despite the fact that the hero is trying to kill the bad guy so he won't change history, the protagonist should feel free to interact with his surroundings without any care. After all, only the bad guy can affect history.
Good guys are immune to that kind of thing.
It's like, you know, a US law or something. That's why I asked you. That's why I asked you. This goes on for roughly two hours, until the audience realizes they don't really care enough about Bob to figure out who the clone is, or the clone decides Bob is such a big loser that he doesn't even want to even bother being his clone. Props can be found by breaking into a junkyard, spraying Elmer's glue all across the parts, and then rolling them through some kid's sandbox while beating them with a crowbar.