Sometimes, i believe there's a white hole to spew out materials. Maybe there's a Magrathea somewhere out there? jk jk... Too much Hitchhiker's Guide to the Galaxy.
But i think there's a limit to how dense an object can be before atoms are too close to squeeze any further. at that point, the hole either just gets bigger or excess atoms are somehow obliterated into tons of energy. I say tons of energy because of E=mc^2. A little mas can be converted into a lot of energy. These are just random ideas though.