Actually, mass does not just  disappear, even if it falls into a black hole. If a black hole has any mass fall into its event horizon, the black hole's mass is increased by that amount. Hence, conservation of mass, and as expected the amount of mass in the Universe remains constant.

cheers,

-avatar!

But it would appear to us that it had "disappeared", right?  I was thinking of it in terms of Jodo perceiving the disappearance of objects in his dream.  The chaos that he described simply reminded me of a video I once saw where it was mentioned that a black hole would spell doom for the Earth.

Unless you want to talk about the Christian concept of 'The Rapture', in which case the law of conservation of mass might very well be violated. ^_~