Rainbow Star
The Rainbow Star is a literal rainbow-colored Star that appears in Super Mario Galaxy. 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 keep running without stopping, he'll get star bits. As well as gaining star bits, if he keeps running, he will spread his arms out while running like when Mario fills his power bar in Super Mario Bros. 3, and he will have longer jumps. 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. Also, the theme associated with the Rainbow Star sounds like a remixed version of the classic invincibility music.