Beat Block Galaxy
Beat Block Galaxy is a galaxy in Super Mario Galaxy 2. This is a very unique stage in which Beat Blocks disappear and reappear to the beat of the music, as the name suggests (it is a pun on "beat-box", where one uses their mouth to make the sounds of hip-hop and electronic music). Another unique feature is that the Wii Remote will beep three times before the blocks swap. These three beeps are also heard elsewhere in the game such as the Flipsville Galaxy, Upside Dizzy Galaxy, and Battle Belt Galaxy. Enemies here include Octoombas (on the green blocks) and Goombeetles (on the yellow blocks), although they aren't present in the prankster comet mission. Mario can visit this galaxy after he feeds a Hungry Luma one thousand Star Bits. The theme that plays here is an arrangement of the Underground Theme from Super Mario Bros. This stage's main mechanic is reused in later games such as Super Mario 3D Land, Super Mario 3D World, Captain Toad: Treasure Tracker, and Super Mario Maker 2.
NOTE: Unless otherwise noted, all names are unofficial.
Beat Block Starting Path
This is the first area the player will travel through. It is basically an L-shaped path. In the first part of the area are a few Beat Blocks separated by purple platforms. Near the end of the path, more Beat Blocks are added and a purple platform connects this path with the second path. Inside the Crystal there is a Goomba.
Beat Block Path 2
This path is a more advanced version of the first one. The first part of the area is completely made of Beat Blocks, so there is no safe spot. There will be a Checkpoint Flag shortly after and then a path connecting to the final area. The Comet Medal is on this path.
Beat Block Pyramid
This area is basically one large pyramid made completely of Beat Blocks except for the corners and platform at the top with five Silver Stars spread throughout the area. During the Step to the Beep, Green Star 1, and Green Star 2 missions, only half the pyramid is present. However, during the Silver Stars in Double Time mission, the pyramid is complete. The only enemies on here are Octoombas and Goombeetles. When Mario has collected the five Silver Stars here, the beat blocks that comprise the pyramid will stop alternating and beeping, and the player is free to collect the Power Star.
Green Star 1
The player will redo the Step to the Beep mission. When the player reaches the purple platform that connects the two paths, they should break the Crystal and then backflip followed by a Spin to get the Green Star in the top left corner. Alternatively, it is possible to reach this Green Star by performing a Triple Jump along the Beat Blocks; rotating the camera so that the Star is in front of Mario facing upwards helps.
Green Star 2
The player will redo the Step to the Beep mission. When the player reaches the Beat Block Pyramid, they should go to the purple platform on the right side. The player must climb on the nearby orange Beat Block and perform a backflip off it followed by a Spin to get the Green Star.
Prima Official Game Guide description
Names in other languages