Lost Souls wander in The Astral Plane while their Earthly selves struggle to break free of obsession. “Some people get caught up in something that isn't necessarily bad—cooking, video games, art,” says director Pete Docter. “But if you do it to the exclusion of everything else in life, you might become a lost soul.”
One of the lost soul attacked 22 and Joe Gardener but they were saved by Moonwind and his crew. He explained that the lost souls were depressed and lonely, so his crew makes some music so they can cheer up the lost soul and free him from his trance. Once the soul was free from his trance, Moonwind helped the soul return to his body where he happily destroyed his computer and tried to get his co-workers to do the same.