The Overset Possessor is the third boss of Luigi's Mansion: Dark Moon. It takes control of the clock face atop the Old Clockworks. The possessor first appears when Luigi makes his way to the belfry. After he scares Luigi, the possessor proceeds to possess the clock face.
The Overset Possessor is a tall, white ghost with three horns. His heart is replaced by the third Dark Moon piece.
The battle with Overset Possessor is quite unique in design. The battle takes place on a giant clock. Starting from 1 and ending on 12, the Possessor turns the clock ahead one hour at a time, summoning new enemies each time. On the 4, 8, and 12 o'clock positions, the Overset Possessor will fight instead. After 4 o'clock, the minute hand will catch fire. After 8 o'clock, the hour hand will catch fire. In order, the enemies fought are:
- One Greenie
- Three Greenies
- Five Greenies
- Two Slammers- Then Overset Possessor attacks
- Two Sneakers
- Three Greenies with shields and hammers
- Three Mummies- Then Overset Possessor attacks again
- Five Creepers
- Red Bombs that attack if you flash them
- A mummy, a Sneaker, a Greenie with a shovel, a Slammer, Red Bombs and a beetle- then Overset Possessor finally attacks again
When he is exposed, the Possessor will charge four times. After his fourth charge, the boss will be stunned, so Luigi can capture him.