At every Final Fantasy game that there's a Moogle, they carry a specific purpose in the game (they can help the player in saving the game's data or simply have their own shop). In Final Fantasy XIII-2, the Moogle named MOG will play a vital role in shaping up the game's story.

Serah, the sister of Lightning in FFXIII was found carrying a Moogle around her. As I mentioned earlier, Mog will play a vital role in Serah's adventure. During battle, Mog the Moogle will have an ability to change into weapons that Serah can use such as a bow and a sword. When not used in battle, Mog can be used on the field by scanning the dungeons with monsters and will provide a Mog Clock.

Whenever Mog turns into a Mog Clock, players can see a clock timer at the bottom of the screen. The needle in the clock will turn into different colors as the time runs out. If the player fails to attack the enemy and the Mog Clock clock made it's full turn, the enemies will attack the player in an aggressive state. To avoid the enemies, simply run away from the radius of the Mog Clock.