“Stay under contROLL!”
—Yellow Toad, Super Mario Galaxy 2
The Rolling Coaster Galaxy is one of the many galaxies found in Super Mario Galaxy 2. As its name implies, this galaxy is similar to a roller coaster and, similar to Rolling Masterpiece Galaxy, Mario (or Luigi) must roll a Star Ball to the end. Also, many Starshrooms appear along the way. It appears to be a reference to the Rainbow Ride level in Super Mario 64 and the Rainbow Road courses in the Mario Kart series. The name of the first mission, The Rainbow Road Roll, in this galaxy confirms this. This galaxy uses the same music from The Princess's Secret Slide, Tick Tock Clock and Rainbow Ride levels in Super Mario 64, which speeds up as the Star Ball rolls faster.
Partway through the level, the path splits in two. One of the Toads says that the right path is for experts, while the other is assumed to be for beginners. In the "Purple Coins on the Rainbow Road" mission, the path for experts is the only path present. The Comet Medal is also on this path. The only enemies found in this galaxy are Bob-ombs and Goombas.