Well, they die like a lot of celestial objects do, with a bang. As I mentioned before, Hawking Radiation, coined by a guy named Stephen Hawking (no, not the crippled dude), dictates that over time the black hole radiates a certain
kind of energy. That energy is called gamma rays. And because e=mc^2 that energy is matter. If matter from the black is finding a way out in the form of gamma rays, then slowly, the black hole will run out of mass to have energy come from. At the end of the Black Hole's life is a big bang, an explosion equivalent to a million megaton nuclear bomb. I hope the animation helps.