Picture of the Dark Moon

The Dark Moon is a crucial part of the storyline in Luigi's Mansion 2. It is the main force in keeping the ghosts of Evershade Valley's peaceful nature, and is destroyed by King Boo in an effort to wreak havoc upon Evershade Valley, and eventually, Mushroom Kingdom. It is shattered into six pieces, each now corrupt with a strange energy keeping it from pacifying ghosts, and each falls into a noteworthy place within the valley. The locations are as follows:

The first piece falls near E. Gadd's bunker.

The second falls near Gloomy Manor, and is taken by the Grouchy Possessor.

The third falls near Haunted Towers, and is held captive by the Harsh Possessor.

The fourth ends up in the Old Clockworks, and is stolen by the Overset Possessor.

The fifth is located in the Secret Mine, and is kept by the Shrewd Possessor.

The sixth and last piece falls into the Treacherous Mansion, and is taken by the Tough Possessor.

All of the Possessors keep the pieces within themselves to make their power grow whilst fighting Luigi.

After recollecting a piece, E. Gadd will "wash off" the energy that is corrupting the piece, and keep it until all the pieces are retrieved. After recollecting all the scattered pieces, it is placed back up in the sky, and the ghosts regain their peaceful composure.