Gif:
https://redd.it/1lauwl2
A supernova explosion that happened in Centaurus A galaxy. This animation represents about 1.5 years of time, omitting the first frame which is a legacy image from 2010. This all happened a bit more than one month after the initial explosion.
What you see here is the fading of the supernova, and then the blueish ring that is a light echo that began to propagate outwards immediately after the initial explosion.
Credit: NASA/STScI/Judy Schmidt