How the Edge of Our Galaxy Defies Known Physics

Don't particles take on extra mass as they accelerate to near the speed of light?  What if "dark matter" is just the extra mass created by hyper-accelerated particles?

Or what if the extra gravity is "leaking" into our universe from a parallel universe?

Or what if every time a particle quantum tunnels to another point in space for an infinitely-short fraction of a second, it removes and redeposits some of its gravity elsewhere in the universe?

Or what if there's an external force "pushing" the outer stars of those galaxies inward, maybe related to the same "pushing" force that causes the universe to expand?

Or what if there's a curve of time over long distances of space that makes the galaxies only look like they're spinning at a faster rate?

Or what if there are just way more neutrinos in the universe than we previously thought?

Or what if our reality is a simulation, and the odd behavior of gravity at large scales is just a programming glitch?