This is weird I was just reading up on antimatter and parallel universes a few days ago, and read that it's possible there is a perfect mirror image of our universe with antimatter instead of matter, but the only way this is possible is if time runs backward in this parallel universe.
It's called CPT symmetry. From the Wikipedia page: "The implication of CPT symmetry is that a "mirror-image" of our universe — with all objects having their positions reflected by an arbitrary plane (corresponding to a parity inversion), all momenta reversed (corresponding to a time inversion) and with all matter replaced by antimatter (corresponding to a charge inversion)— would evolve under exactly our physical laws. The CPT transformation turns our universe into its "mirror image" and vice versa. CPT symmetry is recognized to be a fundamental property of physical laws."