Dark Matter

I have always had an uncomfortable feeling when ever any one ever mentioned this invisible matter. And in looking around Wikipedia ran across a definition for event horizon. The description of what falling into a black hole would be like. In the finale moment The visibility of the object become 0 but the mass of the object become infinite.
Here is my problem with this assuming that this is so and I am then only one black hole would be sufficient to swallow up the universe, but a black hole only has a limited effect area. My question is where did all of this unlimited gravitational effect go? It certainly is not in this universe.

The event horizon for an outside observer really acts as a horizon. He sees an object falling toward the horizon approaching it, but (in his own proper time) never reaching it. In his observations the object goes slower and slower toward the horizon and at the same time the redshift increases beyond bounds to infinity. Also the intensity of the falling object quickly becomes zero. In a finite time the outside observer will receive the last photon from the falling object. He will never see the falling object passing through the event horizon.