Newer Super Mario Bros. Wiki
Game(s) Newer Super Mario Bros. Wii
Newer SMBWii Plus
Appearances (Wii) Spookloft Tower
(Wii) Delusion Castle
Related enemy Boo

Boolossus (also known as Big Boo) is the tower and castle boss of Pumpkin Boneyard in Newer Super Mario Bros. Wii. It's an extremely large Boo.

Boolossus is fought in Spookloft Tower and Delusion Castle.


Boolossus looks identical to a Boo aside from its size. Its a circular white ghost with two stubby arms and a stubby tail. It has two small black eyes under a sinister unibrow over a big red white- and sharp-toothed mouth holding a pink tongue. At the start of its fight, when it is hit, and when it is defeated, it is shown visibly blushing with a pinkness going over its face.


As the player enters the arena, they'll find themselves in a dark room as two Glow Blocks drop from two Warp Pipes beside them. Kamek soon swoops in, using his magic to enlarge a Boo hidden within the darkness, transforming it into Boolossus. Boolossus is initially scared, as with most Boos when the player is looking at them, thought it quickly overcomes this fear, laughing before going for the player and initiating the fight.

Boolossus will continuously go towards the player similar to a Boo when the player turns their back. The fight itself takes place within a hallway.

Boolossus in the midst of being pushed back by a Glow Block.

To fend off Boolossus, the player must throw Glow Blocks provided to them via Warp Pipes at it to push it backward and stall it for a bit before it goes towards the player again. Once a Glow Block has been used, a new one will takes its place as Boolossus absorbs the thrown one. Boolossus cannot be pushed back by stationary Glow Blocks.

In order to defeat Boolossus, the player must press a ? Switch found at the end of the hallway through pushing it with Glow Blocks. Once this ? Switch is pressed, the light will turn on, defeating Boolossus instantly.

Once Boolossus is defeated, it will shrink before disappearing, ending the fight.

There is only one notable difference when comparing Boolossus' tower and castle fights, and that is the addition of spikes in the floor of its castle fight. All other aspects are relatively the same between the two fights.


  • If a Glow Block is relatively close to Boolossus, it is not recommended to go for it, as it will probably catch up to the player by the time they run and grab it. This tip is most useful for the start, as going for the Glow Block to the player's right probably won't result in anything good compared to going for the one to their left.