Rainbow Star

The Rainbow Star is a literal rainbow-colored Star that appears in Super Mario Galaxy and Super Mario Galaxy 2. It transforms Mario into Rainbow Mario. Much like regular stars, this star causes him to turn invincible. When Mario uses the Star, he becomes a rainbow color and leaves a trail of light behind him whenever he runs. If Mario keeps running without stopping, he'll get Star Bits. and be able to jump farther. As it wears off, the music, and Mario's running, will get faster and faster until it ends. The Star might have been differently-colored to differentiate itself from normal stars which are, in 3D games beginning with Super Mario 64, the items to collect to complete the game. The theme that plays after getting a Rainbow Star is a remixed version of the classic invincibility music.

Trivia

 * It is the only power up in Super Mario Galaxy 2 to not appear in the engine room of Starship Mario.