red giant
After a star becomes a red giant, it will take one of several different paths to end its life. Which path is followed by a star after the red giant phase depends on its mass. During the fusion life of a star, its size is the result of a competition between fusion heat pushing the material out and gravity pulling the material in. At the end, gravity always wins. After the star has lived through its red giant stage, the fusion essentially ends the star runs out of fuel allowing gravity to collapse the star. Some of the outer layers of material will be blown away and the core becomes smaller and denser. The core will become either a neutron star, a white dwarf, a black dwarf, or a black hole.