Grand Star

"Oh, thank you for saving the Grand Star, Mario. These star people are my family...they mean so much to me."

- Rosalina

Grand Stars are large and powerful Power Stars in Super Mario Galaxy and Super Mario Galaxy 2. There are seven in the first game and six in the second game for a grand total of thirteen.

In Super Mario Galaxy, Grand Stars are used to provide power to the six domes onboard the Comet Observatory, thereby allowing the player to reach more galaxies as the events of the game progress. In Super Mario Galaxy 2, Grand Stars still allow the player to reach more and more galaxies, but they now provide direct access to the next World via their transformation into a Portal instead.

Super Mario Galaxy
Super Mario Galaxy is the first game in which Grand Stars appear. Bowser has taken all of the Grand Stars and is using them for his own evil intentions. As Mario recovers them, he gradually gains access to different parts of Rosalina's Comet Observatory, as the Grand Stars are the power source of the Comet Observatory's Beacon, which in turn sustains all life onboard the observatory. As each Grand Star is found, a path to the next dome is created. Counting the Grand Star obtained from clearing Bowser's Galaxy Reactor, it is only required to obtain 6 of the 7 Grand Stars to complete the game. The Grand Star from the Engine Room can be completely skipped, as Bowser's Galaxy Reactor can be unlocked as soon as the player clears the previous dome (provided they have 60 Power Stars).

Super Mario Galaxy 2
Grand Stars make another appearance in Super Mario Galaxy 2, the 2010 sequel to Super Mario Galaxy. In this game, the Grand Stars are once again under the control of Bowser and Bowser Jr. This time around, Grand Stars restore power to Starship Mario, and also create the Portals leading from one World to the next. In addition to this, the Grand Stars in this game are apparently responsible for Bowser's huge size, as he has eaten them to make himself considerably larger. After Mario defeats one of Bowser Jr.'s machines or henchmen, it will explode and release a Grand Star. After Mario defeats Bowser, he will cough up a Grand Star. During the final battle in Bowser's Galaxy Generator, he is actually able to swallow the Grand Star again, making himself a great deal larger than he had been, and leading to one final segment of the battle. The Grand Stars seem to have an interesting side effect when misused, one that causes Bowser to become extremely tiny after the final battle, as seen in the end credits of the game.

Mario Kart series
While Grand Stars have not appeared physically throughout the Mario Kart series, they have been consistently used as Rosalina's emblem, and later, Baby Rosalina's as well. In the latter's case, the emblem features a Grand Star inside blue bonnet frills.

Mario Kart 8 / Mario Kart 8 Deluxe
In Mario Kart 8 and Mario Kart 8 Deluxe, a floating Grand Star replaces the star icon that can be seen rotating on top of the tower in the city in N64 Rainbow Road.

Mario Kart Tour
Grand Stars appear in Mario Kart Tour as collectibles, earned by attaining a certain score after each race, completing one of the World Tour challenges, Gold Pass challenges, or daily challenges. To unlock more cups and progress further through each tour, a certain number of Grand Stars is required. Each tour gift also requires a certain number of Grand Stars to open. When the player has opened every tour gift, the next Grand Stars earned will each be converted to one hundred coins, and when a new tour begins, the total is reset to zero. Rosalina (Swimwear)'s teal swimdress is also decorated with Grand Stars.

Super Smash Bros. Ultimate
Rosalina's Final Smash in Super Smash Bros. Ultimate utilizes a Grand Star, in place of the Power Star from the previous installments.

Other appearances
Rosalina's emblem is a Grand Star throughout many of her other appearances, including Super Mario 3D World, Mario Tennis games, other sports games, and the Mario Party series. In Super Mario 3D World, her emblem can be seen whenever she grabs a Goal Pole or touches a Checkpoint Flag, and on Rosalina's Character Switch. In Mini Mario & Friends: amiibo Challenge, the Grand Star is similarly used to signify Mini Rosalina's levels.

In the Super Mario Mash-Up Pack in Minecraft, Nether Stars are replaced by Grand Stars.

Mario Kart Tour

 * Mario Kart Tour Twitter: "Collect Grand Stars by earning points in races or by testing your driving skills in challenges! The more Grand Stars you earn, the more Cups and Tour Gifts you unlock. Try to collect enough Grand Stars to unlock everything in a single tour!"

Trivia

 * Bowser Jr.'s Fearsome Fleet is the only galaxy where Yoshi is able to pose with Mario when the Grand Star is collected. In Bowser's Galaxy Generator, Princess Peach, Luma and the Co-Star Luma (if used) will pose with Mario. If Mario also brings Yoshi to the end of the level with a glitch, they will not pose since there is no special animation that Mario and Yoshi have with that Grand Star.
 * The Grand Star from Bowser Jr.'s Lava Reactor is the only one across both Super Mario Galaxy and Super Mario Galaxy 2 that is optional, as Bowser's Galaxy Reactor can be entered as soon as the player collects the Grand Star from Bowser's Dark Matter Plant and collects 60 Power Stars, and the Garden (which the Lava Reactor's Grand Star unlocks) is not necessary to do either.