possibly the largest comet ever discovered. Comet BB.
Astronomers in New Zealand were the first to spot a coma, or zone of gas and dust, spreading around the megacomet C/2014 UN271, also known as Bernardinelli-Bernstein, which may be 1,000 times more massive than a typical comet. It could be the most massive comet ever found in all of recorded history.
Bernardinelli-Bernstein's closest approach to the sun will still be beyond Saturn in January 2031.