Black holes are an object in space that contains the density thought to be infinite enough to create a gravitational field great that light cannot escape it's gravity beyond a certain point known as the even horizon.
Black holes are formed by a hyper giant star collapsing in on itself. This is when the radiation force of a star is less than of that of it's gravitational force thus causing the core to allow the star to collapse in on itself or implode. When a hyper giant implodes, sometimes it can have a very high density and become a black hole. These objects can hold massive amounts of other bodies around them. In spiral galaxies, these black holes are known to be located at the center and they contain stars in which they orbit around the black hole. These black holes usually have millions to trillions of stars orbiting them.
Black holes can also destroy objects atomically. When a body gets too close to the black hole, the gravity by the black hole will get stronger relative to the body getting closer to the black hole and the black hole will either rip it apart from atom to atom or it will become super heated plasmatic material. Depending on the size of the black hole and the mass, these can/will occur.
Though, these black holes sound like they don't have a death cycle, they do, but it hasn't been achieved yet. Hawking Radiation is the idea, from Stephen Hawking, that quantum field theory can explain that a black hole can lose energy over time and shrink and then eventually be spread out into cloud of material rather than a dense object. They have used the center of the galaxy's black hole, Sagittarius A, to observe this idea and have looked at the magnetic field of the black hole and the first photo every released was in early 2016. This is a great initial result stating that black holes do emit radiation with the studies done previously can conclude Hawking Radiation to be a real thing.