"Two supermassive stars can collide, this causes an event called a Gamma-Ray Burst.
A supernova is an explosion so powerful that a single star can briefly outshine an entire galaxy. A gamma ray burst is that, except much bigger and with all the energy focused into a beam.
If there’s a relatively close hit with a somewhat close origin. The first we’ll know of it is if the beam fries us or at least f@#ks up the ozone layer.
We suspect that this has happened once before, and it wiped out the majority of the Earth’s biosphere."