Grouchy Possessor is a tall, white ghost with a single horn. It is the Possessor Ghost seen in the ending credits.
During his boss battle, the Possessor contains a Dark Moon star within his heart.
BattleIn battle, Grouchy Possessor mainly possess the body of a mother spider and uses many attacks against Luigi. First, he can lob poison blobs at Luigi from a distance and can summon smaller spiders to aid it as well. It can also slam the ground if Luigi is close enough to him. Without the spider body, the Grouchy Possessor can attack Luigi by charging at him. Grouchy Possessor himself has infinite HP.
Even though Grouchy Possessor has infinite HP, he can still be sucked up. However, Luigi must endure three phases of the fight.
For the first phase, Luigi must stun the Grouchy Possessor with the Strobulb when he opens his eyes. Next, Luigi must vacuum the ball of web and bring it back to the suit of armor with the lit torch avoiding the poison blobs and spiders along the way. The fire will tread all the way back to the large spider and it will start to burn and the Grouchy Possessor himself will come out. Luigi must then stun him with the Strobulb and start to suck him up. The Grouchy Possessor will escape back into the spider body, attempt to ram Luigi, and Phase 2 starts.
For this phase, Luigi must head toward the web that is hanging down from the ceiling and start to spin it around. Once it catches on fire, the web should burn away a suit of armor with a spear. Next, Luigi must stun the Grouchy Possessor again with the Strobulb and grab the web under him. This time, Luigi must lure the web to the suit of armor with the spear and wait for it to jab the web. With the web stuck, Luigi must once again spin the brown web around until it catches on fire with the web the suit of armor has and the Grouchy Possessor will get burned and come out again. Luigi must repeat what he did in Phase 1 and now, Phase 3 starts.
For the final phase, Luigi must grab a loose web ball and take it all the way back to the suit of armor with the torch. After lighting the web ball has been set on fire, Luigi must head closer to the Grouchy Possessor and burn away a series of webs revealing another Suit of Armor with a torch. Luigi must then repeat everything from Phase 1 and the Grouchy Possessor will be finally caught. After being defeated, the first piece of the Dark Moon is recovered.
|Luigi · Professor E. Gadd · King Boo · Mario|
|Ancient Poltergeist · Boo · Creeper · Gobber · Greenie · Gold Greenie · Hider · Poltergeist · Polterpup · Slammer · Sneaker · Strong Gobber · Strong Greenie · Strong Hider · Strong Slammer · Strong Sneaker · The Three Sisters|
|Grouchy Possessor · Harsh Possessor · Overset Possessor · Shrewd Possessor · Tough Possessor · King Boo|
|E. Gadd's Bunker · Evershade Valley · Gloomy Manor · Haunted Towers · Old Clockworks · Secret Mine · Treacherous Mansion|
|Dark Moon · Dark-Light Device · Dual Scream · Golden Bone · Key · Poltergust 5000 · Strobulb|