Atomos is a Pulse fal'Cie that digs underground tunnels along the Mah'habara Subterra. Its appearance is akin to a spherical boulder with a spinning circumference of glowing spikes. The fal'Cie also serves as a transport for whomever can stop it, possessing a partially hollow interior. Stopping it is no mean feat—it requires a great force; in the case of the heroes, a number of Juggernauts team up to halt Atomos. Afterward, the player is able to ride Atomos between Mah'habara Subterra and Sulyya Springs, as well as use him as platform to access previously inaccessible parts of the mine.
- Atomos's model exists in the game disc of Final Fantasy XIII-2 in two versions, one close-up, more detailed model, and one model for viewing further away. Atomos never appears in the game, however, making the models dummied features.