A supernova is the fourth stage of a star's life. It increases its luminosity a lot more because of a catastrophic explosion, turning to a colorful, beautiful-looking supernova.
The founder of the very first supernova was Johannes Kepler, in October 9, 1604.
A supernova is formed when a star loses its nuclear fuel, and the mass flows to its core. The core then gets so heavy that it loses gravitational force, and there would eventually be a catastrophic explosion.