A mysterious, smiling koala that Lower Decks characters see when they brush against death or higher planes of existence, hinted to be bound up with the workings of the universe.
The Koala is a recurring cosmic joke in Lower Decks. It is first seen in the first-season episode Moist Vessel, when Lieutenant O'Connor, who has spent years trying to ascend to a higher plane, finally does so. As he dissolves into energy he perceives the secrets of the universe, among them an enormous koala, and wonders in his last moments why it is smiling.
The animal returns in the second-season finale First First Contact. Brad Boimler nearly drowns in the Cetacean Ops tank and, on being revived, speaks of having seen a koala. The image sits alongside the black mountain that Shaxs associates with his own unexplained return from the dead, a subject the crew have learned not to raise with him.
The series never explains what the Koala is. It remains a deadpan suggestion that something benign, and faintly ridiculous, sits behind the Star Trek cosmos.