Dark energy as backwards gravity

Dark energy continues to be elusive. Perhaps the effect attributed to dark energy is really caused by gravity with an opposite arrow of time. If there are multiple universes do they all have to be facing the same way? Perhaps some have opposite entropy with a corresponding opposite arrow of time.

It could also be that the big crunch (opposite of big bang) has an opposite arrow of time for internal observers. They would see what they think is an expanding universe. In fact we could be living in the big crunch and not realize it.

Either way there could be a bleed thru of negative gravity into our realm, acting like what we expect of dark energy.