Luma

Lumas are star-like creatures that appear in Super Mario Galaxy. Unlike most Stars, they have a tear drop-like shape, and come in many colors. They are much like Power Stars, but they are more circular in shape and able to talk.

Lumas boast the ability to transform, from minor planetoids to entire galaxies. They seem to acknowledge Rosalina as their "mama". According to Rosalina, some can transform into Power Stars. Most of them make their home in the Comet Observatory, while others live on Starship Mario.

Colors
Lumas come in many different colors, different colors have different abilities.
 * Yellow - Transforms into a Launch Star or Sling Star
 * Blue - Transforms into a Pull Star
 * Hungry and Pink - Transforms into a Planet or Galaxy
 * Pink - Transforms into a Pink Launch Star
 * Green - Guards the Trial Galaxies. As stated by Polari, they will transform into Green Power Stars
 * Red - Guards the Red Star

Only one cream-colored Luma is seen; he is known as Baby Luma, although the Luma that transformed into the comet that Rosalina and the Lumas travel on appears to be cream-coloured in Rosalina's storybook's illustration. He is the Luma that Rosalina gives Mario in the beginning of the game. Luma grants Mario the power to do Spins. Yellow Lumas transform into Sling Stars and Launch Stars and are the most common variety. Red Luma guards Red Stars. Green Lumas are the guardians of the Trial Galaxies and transform into green Launch Stars. Blue Lumas transform into Pull Stars, Pink Lumas who turn into pink Launch Stars in order to get to hungry Luma galaxies and a large Light Blue Luma hosts the Luma Shop. There is also another type of Luma that are pink in color, known as Hungry Lumas. They seem to be more physically mature than other Lumas, as they eat heavily as if they are going through a growth spurt. The last type of Luma is a purple Luma that holds the power to move Prankster Comets.

In the end, all the Lumas (including "the" Luma) throw themselves into the massive black hole created by Bowser's dying sun to neutralize it. However, Luma is reborn and living on a small planet while it is hinted that the other Lumas will be reborn later. Indeed, they appear in the sequel.

In Mario Kart Wii, a Yellow Luma revolves around Rosalina at all times. It has no effect on gameplay.

Lumas appear in Super Mario Galaxy 2. They look the same as they did in Super Mario Galaxy. There is also Lubba, a large purple Luma who acts as the head of the Lumas in this game and an exceptionally large species of Luma in the Supermassive Galaxy.

Trivia

 * Paper Mario featured a similar species, called Star Kids. Like the Lumas, the Star Kids were young stars, who were raised on a special place to become real stars someday. They also possessed magical abilities, like the Lumas, and a very similar, childish behavior.
 * The name Luma comes from the Latin lumin, which means "light." It is a reference to their similarity to the Power Stars and their future as stars.
 * Although the Luma that appears next to Rosalina in Mario Kart Wii is a Yellow Luma, Polari was usually the Luma at her side in Super Mario Galaxy.