Rainbow Star

From the Super Mario Wiki

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 keepd on 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.

Stars

Beanstar | Big Star | Bonus Star (Mario Party) | Bonus Star (Super Mario World) | Cobalt Star | Crystal Star | Crystal Stars | Diamond Star | Dark Star | Eldstar | Emerald Star | Garnet Star | Giant Power Star | Gold Star | Grand Star | Green Power Star | Kalmar | Klevar | Launch Star | Luma | Mamar | Millennium Star | Misstar | Muskular | Polari | Power Star | Pull Star | Rainbow Star | Red Power Star | Red Star | Ruby Star | Sapphire Star | Shine Sprite | Shooting Star | Silver Star | Skolar | Sling Star | Star | Star (Donkey Kong) | Star (species) | Star Piece | Star Spirits | Starslap | Star (outer space) | Twink | Warp Star | Zeostar