Species: luma
Lumas are star-like creatures that first appear in Super Mario Galaxy. Unlike most Stars, they have a rain drop-like shape and come in many colors. They are much like Power Stars, but are more circular and have the ability to talk. The Lumas are all very friendly and assist Mario during his quest. Lumas have the ability to transform, from minor planetoids to entire galaxies, and according to Rosalina, some Lumas can even transform into Power Stars. They call Rosalina their "Mama". Most of them make their home with her in the Comet Observatory, and others live on Starship Mario following their leader Lubba. Their name comes form the Latin word for light, lumen, which is a reference to their future as stars. In Super Mario Galaxy 2, if the Co-Star Luma spins one, it will emit three Star Bits.
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. In addition, Blue Lumas look similar to an item in Paper Mario: The Thousand-Year Door called Mini Mr. Mini.