Boulder Bowl Galaxy

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

Starting Planet
The starting planet has a glass cage with a Rock Mushroom in it which is guarded by three Octoombas. Two members of the Toad Brigade are found here. It has also a huge purple crystal and. The Comet Medal is trapped inside. It has also a giant rised bridge that, after been dropped, can help Mario access an area with Pinheads.

Rolling Rocks Planet
This planet is an area with a glass cage, but, this time, a Launch Star is trapped in it. Mario has to defeat a group of Octoombas to open the cage. There are two boulders rolling around the cage.

Boulder Planet
This planet has a Luma on it, some shiny spots on the ground, rolling rocks, Octoombas and Incoming Chomps. It also has a Rock Mushroom and three rock pillars. And most important, a giant purple crystal with a Launch Star trapped in it. In a later mission there is a golden Gearmo in here. If Mario lures a Goomba (which is found hiding inside a rock) towards it, he will reward the plumber with a Star.

Yellow Crystalic Planet
This is a crystalic planet, a Luma Shop can be found on it, as well as a Launch Star and a Midway Flag.

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

Rock and Rollodillo
To get the Power Star, Mario must first get the Rock Mushroom trapped in a glass cage in the first planet. To do so, he has to defeat the three Octoombas protecting it. After getting the Mushroom, Mario will transform into Rock Mario, which allows him to roll and break things.

To process, the plumber has to use his Rock form to hit the rised bridge and make it fall. Then, he should bowl over the Pinhead and process to the next planet. Here, he has to get to the Launch Star trapped in a glass cage. To do so, he must defeat all the Octoombas found in this planet. When using the Launch Star, he'll find himself on a planet with a Luma who tells him that if he uses the shiny spots on the ground, he'll gain some health. To process, he has to use his Rock Form again and break the giant purple Crystal where the next Launch Star is trapped. After using it, he'll get to a yellow crystal planet with a Midway Point and a Launch Star which blasts him to the boss planet.

After defeating Rollodillo, he'll explode and leave a Power Star which Mario has to get.

C'mere, Goomba
To unlock this mission, Mario must get a letter from Gearmo saying that he needs help in Boulder Bowl Galaxy. Mail Toad will recieve the letter after Mario collects sixty Power Stars or more. After reading the letter, Mario has to go to this galaxy and make his way to the Boulder Planet. He'll find Gearmo searching for a Goomba. The plumber can find one by breaking one of the rock spikes found on this planet. He can do so by using his Rock Form. When the Goomba comes out, he'll chase Mario. Mario must lead the Goomba to Gearmo's trap. With the enemy caught, Gearmo will thank Mario and reward him with a Power Star.

Rolling Crabber Romp
Mario has to go to this galaxy when the Prankster Comet is unlocked. He'll end up on the Cage Planet that, this time, is full of crabs. Mario has sixty seconds to defeat all of them using the Rock Mushroom. If done so, he'll be granted with a Power Star.

Trivia

 * The first level's name "Rock and Rollodillo" is based on the famous music type "Rock 'n' Roll".