Third Area: Boolossus (2)

Meet the 15 dancing Boos on Balcony 3F to initiate the boss battle.

Boolossus, the large form of the 15 Boos, will appear. The battle takes place on the balcony, with frozen unicorn statues serving as your primary weapon. Luigi rides the vacuum, making movement fast but slippery.

Boolossus will jump at you. Quickly move to the left or right, position yourself in front of a unicorn statue, and dodge when Boolossus attacks. This should shatter it. Avoid direct frontal attacks from Boolossus.

After Boolossus shatters, the 15 Boos will scatter. Ice Ghosts will appear near the unicorn statues.

Vacuum an Ice Ghost to gain ice power. Use the L button to freeze nearby Boos.

Vacuum the frozen Boos. When many are present, they are easy targets. Fewer Boos make them more dangerous and aggressive. If you stop spraying ice, they will attack.

When only one or two Boos remain, they become harder to catch. Use the shoot function (press L repeatedly) to defeat them. Stay at the lower part of the screen to easily target them. Vacuuming a frozen ghost refills your ice element.

The Boos will reform into Boolossus periodically. Make Boolossus hit a unicorn horn again. Boolossus shrinks as fewer Boos are inside it, becoming faster but also easier to hold in your vacuum beam. If held, steer it towards a unicorn horn.

Continue this cycle of shattering Boolossus and defeating the individual Boos until all 15 are vanquished.

Upon defeating the last Boo, you will win the battle, receive the key, and clear the area.