IC 1101 is a supergiant elliptical galaxy at the center of the Abell 2029 galaxy cluster, approximately 320 megaparsecs (1.04 billion light-years) from Earth.
To this day it is one of the largest known galaxies in the observable universe, only narrowly beaten out by several others. It is estimated to have 100 - 150 trillion stars, a radius of 3 mega-light-years, and a total mass of over 1.125 quadrillion solar masses. It's central black hole alone is over 70 billion solar masses.
To put the scale into perspective, if this galaxy were centered on the Milky Way, it would engulf over 60% of it. It is three times wider than the distance between the Milky Way and Andromeda.
It is unclear what exactly is going on currently within the galaxy. Billions of Dyson Swarms and other mega-structures have been detected over the years. Multiple instances of Black hole Bombs going off have also been recorded.
All signals and light from the galaxy is over one billion years old, so current events are entirely unknown. All that is known is that there are likely thousands of different civilizations calling this galaxy home. Most of which are estimated to be over one trillion stars strong. Were a civilization to fully colonize this galaxy, they would be considered a type 3.3 civilization.