King Boo's Illusion

King Boo's Illusion is the final place visited in Luigi's Mansion: Dark Moon, and it is here where Luigi battles the Tough Possessor and King Boo, as the final boss.

History
After Luigi stabilizes the world's dimension, he enters the portal to find the last Dark Moon piece. Upon arriving, Luigi winds up in a large room with knight statues. Here, Luigi battles the Tough Possessor which possesses multiple suits of armor and a gigantic suit of armor as a last attempt to defeat Luigi.

Upon defeating the Tough Possessor, Professor E. Gadd tries to pixelate Luigi out, to meet him in the Bunker. However, the transmission is intercepted by King Boo, and Luigi is placed back into the illusion world. King Boo then starts taunting Luigi by making windows visible, where the player can see King Boo's silhouette outside, and laughing at him. After the taunting, Luigi looks up, only to see Mario trapped in a painting. He reaches out, but King Boo appears behind the painting, which turns out to be a illusion. He then starts talking to Luigi, about his incarceration in a painting and about his escape. He then announces that "he returned to paint the town red" and become the supreme ruler of the Mushroom Kingdom. He then accumulates energy from his crown, and reveals the arena for Luigi and King Boo's battle. The arena is surrounded by electricity. However, it will not inflict any damage to Luigi.

Battle
In the 1st phase of battle, King Boo will summon 3 spiked balls by slamming into the platform, creating a ripple; which causes the spiked balls to land heavily on the ground from high above. The place where they will land is predictable due to the shadows they cast before landing. They will roll around the arena as the platform tilts because of Luigi's weight. As King Boo cannot move if Luigi faces him with the flashlight, the player must manage to immobilize King Boo right under one of the falling spike balls. The spike ball will flatten King Boo, revealing his HP (of 100). Luigi must then vacuum him, while being careful of the moving spike balls. During the capture however King Boo will try to pull Luigi into any remaining spike balls. He will also attempt to break the Poltergust's connection by slamming into the ground again. Luigi will then manage to completely vacuum him.

King Boo is not yet defeated, however. He will manage to escape from the vacuum, because of his jewel on his crown, and will slam the platform hard, destroying the sides of it and causing it to tilt downwards. Luigi will then slide down, and be flung through a window inside a mansion hallway. In this phase of the battle, Luigi must run through the hallway, while avoiding obstacles, and being aware of an enormous King Boo rolling towards him from the left which is destroying the hallway. Different obstacles await him, though: drawers, suits of armor, ice & sand patches and fake stairs. King Boo also uses the crystal on his crown to make more sand patches, or by making the drawers spring out, blocking Luigi's way. Hearts and Gold Bars are also found here. If Luigi is hit by King Boo he will lose 20HP and King Boo will mock him allowing Luigi to get a bit ahead of King Boo. Upon standing on a spring at the end of the hallway, Luigi will jump out, and land on an identical platform as before, King Boo will then emerge from the hallway, destroying it completely, and returns to normal size. The player must repeat this process two more times to defeat King Boo.

The second & third time Luigi verses King Boo in the arena he creates sand, ice and spike patches to mess with Luigi's chances of winning. He also introduces a Large spike ball as well. He will also try to ram Luigi. On the third time King Boo will shock all but one part of the arena three times. Luigi has to get to the spot where the lightning doesn't hit to avoid damage.

After defeating King Boo, Luigi picks up his power-enhanced crystal which returns him to the Terrace where Mario's painting was all the time, hidden by Spirit Balls, that disappeared after King Boo's defeat.

In-Game Description
''King Boo has created the ultimate illusion and he's waiting for you to show yourself. Are you brave enough to face him in his own territory once again?''