What is the most violent star death called

Hi there!

The most violent star death is a Supernova. This is the massive explosion of a supergiant star as it's fuel source runs out and it can no longer fuse iron at its core safely. This causes the star to swell to unstable sizes until it explodes in a Supernova. The amount of energy that is output during a supernova is equivalent to all the energy our own Sun outputs in its whole lifetime.