Bouldergeist

Bouldergeist is a boss in the game Super Mario Galaxy. Its name is a pun on boulder and poltergeist. It is the boss of the Ghostly Galaxy. It seems to be based on Eyerok from Super Mario 64.

Appearance
Bouldergeist is essentially a stone column with a face. He has two enormous stone hands. Bouldergeist's attacks include tossing rocks at Mario, slapping his hands on the ground, punching at Mario, and summoning lines of spiky rocks from the floor. He is fought in a plain circular arena.

Combat
To defeat Bouldergeist, Mario must swing Bomb Boos into him. After three hits, he turns into a shadowy form that floats around. Swinging a Bomb Boo at the shadow will cause Bouldergeist damage. This causes Bouldergeist to return to his column form and reveal his hands. Bouldergeist then has a greater variety of attacks. Mario must once again swing three Bomb Boos into him and then swing one final Bomb Boo into his shadow form to defeat the malevolent stone creature and claim his Power Star.