Bouldergeist

Bouldergeist is a boss in the game Super Mario Galaxy. Its name is a portmanteau of boulder and poltergeist. It is the boss of the Ghostly Galaxy and is destroyed by Mario in battle. Bouldergeist returns in Super Mario Galaxy 2 as the fourth and second-to-last Super Mario Galaxy boss encountered in the Boss Blitz Galaxy. Its attack tactics match in both games.

Appearance
Bouldergeist is essentially a huge column of rocks roughly shaped into a face, and its insides are made up of shadows. However, its true form is not revealed until his rock armor been destroyed, revealing a face with a red uvula hanging from the bottom. In its rock form it has two enormous stone hands, which are used only in the second half of the battle. Bouldergeist's attacks include tossing rocks at Mario, summoning lines of stalagmites from the floor, and in the second half of the battle, slamming its hands on the ground and punching at Mario. It is fought in a plain circular arena.

Combat


This battle practices Mario's use of the Bomb Boo. To get Bomb Boos, Mario must dodge the black rocks that the Bouldergeist throws at him. Once they hit the ground, they will turn into Bomb Boos. Each hit will gradually cause Bouldergeist to lose a bit of its stone layer. Three hits will completely destroy the entire stone layer surrounding Bouldergeist's real form. Once this happens, Mario has to, yet again, spin a Bomb Boo at the shadow's red bubble to inflict more damage on Bouldergeist. However, the fight is not over, as Bouldergeist regains its old stone layer, and reveals its large rock hands. Bouldergeist then has a greater variety of attacks, as well as a larger form of protection. Mario can, however, destroy the hands the same way, but they regenerate after a short time, so Mario has to damage Bouldergeist before the hands reappear again. Mario must once again swing three Bomb Boos into it, and then swing one final Bomb Boo into its shadow form to defeat the Bouldergeist and claim its Power Star. Also, Bouldergeist may shoot golden rocks which reveal a coin. It only shoots 20 coins though.

Bouldergeist's attacks consist of a boulder throwing attack that Mario can only run from, and summoning a row of stone spikes out of the ground, indicated by dark shadows appearing where the spikes will be. The spikes will not harm Mario after they are out of the ground and can be broken with a spin attack. After the boss forms its hands, it has new attacks in addition to to the old ones. If Bouldergeist draws back its fist, it is preparing to punch Mario. Bouldergeist cannot change directions once it starts the attack so it is easily avoided and used to destroy any stone spikes. Bouldergeist can also use a slap attack that will crush Mario if not dodged, though it does not cause instant death. A fair warning is given when Bouldergeist holds its hands over the surface of the planet before they drop. Also, Bouldergeist's stone spike attack forms two rows of spikes that Mario has to avoid. Bouldergeist's inner form is too weak to attack Mario. It may only flee and summon Bomb Boos.

Later, Mario must defeat it with one wedge of health under the Daredevil Comet to claim Bouldergeist's second star. Bouldergeist will no longer throw golden rocks.

Trivia

 * Bouldergeist closely resembles Bogmire from Luigi's Mansion, as they have the same mouth and eyes. In addition, both are ghosts and both summon smaller, shadow-like ghosts to attack. The arena he is fought looks a lot like the arena bogmire is fought in.
 * Bouldergeist's slap attack is the only instance in Super Mario Galaxy in which Mario can get crushed without instantly dying. After Mario is crushed, he will just vibrate, pop back up after a few seconds, and lose one health point, similar to when he survives being squished in Super Mario 64.
 * Bouldergeist has unused animations for popping into and out of the ground, and when he does this his true form appears with a somewhat beta design.
 * Bouldergeist's design makes an appearance in Mario Kart 8's Twisted Mansion as an arch leading to the underwater section.
 * Bouldergeist's design bears a heavy resemblance to Cackletta's form Cackletta's Soul from Mario & Luigi: Superstar Saga, with similar horns, identical eye color, and similar attack pattern.
 * Boldergeist shares his music with Kingfin.
 * The toads say that Luigi was caught by Bouldergeist, but Mario never rescues Luigi in the mission and is not even seen.