Dark matter doesn't necessarily need to be viewed as this super weird thing. It seems to be simply some unknown substance that exerts gravitational force while

Dark matter doesn't necessarily need to be viewed as this super weird thing. It seems to be simply some unknown substance that exerts gravitational force while not interacting or only very weakly interacting with most other forms of matter / energy. We have seen somewhat similar things before. Neutrinos interact very weakly with matter. A single neutrino needs to pass through a stack of lead that is an entire _light year_ in length just to have a 50% chance of hitting a single atom (yes, 1 actual light year). And we have certainly have encountered unknown substances and particles before. My layman's understanding is that no variation of MOND has managed to get that close to the comprehensive and robust scope of explanation provided by general relativity.