Boulder Bowl Galaxy

Boulder Bowl Galaxy is a galaxy found in World 2 of Super Mario Galaxy 2. The galaxy introduces and utilizes the use of the Rock Mushroom that turns Mario into a solid boulder. Some planets included in the galaxy are made of rocks, soil and steel platforms. Bowling pin-like enemies called Pinheads are found in the galaxy, which Mario can bowl over by rolling over them in his boulder form. Rollodillo is fought here. The music in the level is the same as in Spin-Dig Galaxy.

Planets
NOTE: Unless otherwise noted, all names are unofficial.

Starting Planet
The starting planet has a glass cage with a Rock Mushroom in it which is guarded by three Elite Octoombas. Two members of the Toad Brigade are found here. The planet also has a huge purple Crystal, where the Comet Medal is trapped inside. A giant, raised bridge that, after been dropped, can help the player access an area with Pinheads is also located here. The area has a ramp that leads the player to the next planet. A little bit beyond the Comet Medal there is a 1-Up Mushroom on a ledge. There are also some rock spikes. They either give the player some Coins, Star Bits, or Enemies.

Rolling Rocks Planet
This planet contains a glass cage and a Checkpoint Flag, but this time, a Launch Star is trapped inside the glass cage. The player has to defeat a group of Octoombas to open the cage. There are three Boulders rolling around the cage. The player only needs to kill the Octoguys and Elite Octoombas. The Boulders are optional to destroy as they just give the player Star Bits.

Boulder Planet
This planet is covered with Boulders, Elite Octoombas and Chomps. It also has a Rock Mushroom and three rock pillars. A giant purple Crystal with a Sling Star trapped in it can be found on the top of the planet. In a later mission, there is a golden Gearmo that can be found on this planet. There is also another rock pillar that has a Warp Pipe inside. The Warp Pipe leads to a bonus area with six Chance Cubes.

Orange Crystal Planet
This is a small, orange-colored crystalline planet. Lumalee can be found on this planet, as well as a Launch Star and a Checkpoint Flag.

Cage Planet
This planet is a large, round, red cage. Rollodillo's battle takes place here. It has Rock Mushrooms that the player can use to transform into Rock Mario or Luigi. It is also the planet where the Prankster Comet mission takes place.

Asteroid Planet
This planet is seen only in Rolling Crabber Romp for this galaxy. In the mission, this planet is the first planet the player lands on, as opposed to the normal Starting Planet. It has nothing on it but a signboard, a 1-Up Mushroom, and a Launch Star which will shoot the player to the Cage Planet.

Green Star 1
The player will redo the Rock and Rollodillo mission. Instead of getting the Rock Mushroom on the Starting Planet, the player must repeatedly wall jump and spin on the sides of the bridge to climb it. At the top of the bridge will be the first Green Star. If the player knocks down the bridge before grabbing the star, there will be no way to reach it unless they were to restart the level.
 * Planets Visited

Green Star 2
The player will redo the Rock and Rollodillo mission once again. The player should get the Rock Mushroom and knock the bridge down. However, instead of rolling up the ramp, the player should walk up it. The second Green Power Star is floating in the air right behind the ramp.
 * Planets Visited

Green Star 3
The player will redo the Rock and Rollodillo mission one final time. They should grab the Rock Mushroom, knock the bridge down, and use the ramp. This time, after landing on the Rolling Rocks Planet, the player should go in a straight line towards an Elite Octoomba. Behind the Elite Octoomba is a wooden fence and the third green star lies right behind this fence.
 * Planets Visited

Prima Official Game Guide description

 * "This galactic quarry is where you first discover the Rock Mushroom, which turns you into Rock Mario. With this new power, you can roll into a boulder and smash through objects and enemies. And there are plenty of enemies in this galaxy, too, just waiting for you to roll through."

Names in other languages
Bröselbrock-Galaxie