Cosmic Mario

Cosmic Mario is a character that appears in Super Mario Galaxy. His physical shape is identical to Mario, while his outer appearance is blue with stars all over, as if he were made out of cosmic matter. He also has an unusually high-pitched voice. If Mario or Luigi enter a galaxy when a Cosmic Comet is orbiting a galaxy, Cosmic Mario appears at the beginning at the level and challenges the player to a race. The player must then race through numerous obstacles and reach the finish before Cosmic Mario to earn a Power Star. If Cosmic Mario manages to reach the Power Star first, Mario will lose a life and must restart the race.

If the player is playing as Luigi, Cosmic Luigi will appear in place of Cosmic Mario. Cosmic Luigi utilizes shortcuts and many long jumps. As a result, he is faster and much more difficult to beat than Cosmic Mario.

Cosmic Mario appears to be the equivalent of Koopa the Quick and Il Piantissimo from Super Mario 64 and Super Mario Sunshine, respectively. Spooky Speedster, also from Super Mario Galaxy, is a racer as well.

Similar entities based on Cosmic Mario appear in Super Mario Galaxy 2 in the form of the Cosmic Clones, the Cosmic Spirit and Shadow Mario. Cosmic Clones return in Super Mario 3D Land.

Trivia

 * At the start of a race, if the player holds the up, then  when the timer hits 2, and then hits  just as the race starts, Mario or Luigi will get an extra boost at the beginning of the race, shown by a yellow color appearing on Mario/Luigi, shrinking gradually, being as a marker of the end of the bonus effect. This move is called the Starting Boost.
 * During the "Underwater Cosmic Mario Race", Cosmic Mario's Koopa Shell is blue.
 * If the player collides with Cosmic Mario/Luigi, Star Bits will come out of him and scatter.
 * Cosmic Mario resembles Shadow Mario from Super Mario Sunshine. The Japanese, German and Korean names for Cosmic Mario mean Shadow Mario.
 * Additionally, the theme played in Super Mario Sunshine when Shadow Mario first appeared can be heard in the Cosmic Mario theme.
 * Cosmic Mario shares its voice clips with the Cosmic Clones.
 * During the scene where you get the star, you can see Cosmic Mario/Luigi looking like he's crouching down, possibly showing the sadness that he lost.