We can only describe something as a substance in a certain extent, with some criterion.If we insist that something is substance, it can only be the all-encompassing universe, or god in spinoza's case,
you can have a cat and you can paint the cat, you can dye the cat's hair, you can go to the local hair salon and you can dye the cat's hair, so it's not gray it's red, it's the same cat so the cat is the substance and grayness or redness or greenness is an accident of that substance" Karl Marx
Yes, that's great.. when someone explains that how a theorist refuted a historical concept using every day examples, we can attribute that example to the theorist. Fun!