Cobalt Star

From the Super Mario Wiki

The Cobalt Star is the name given to the power source for Professor E. Gadd's time machine. The Cobalt Star was unfortunately shattered into the Cobalt Shards, forcing the Mario Bros. to go on an extensive journey to retrieve them, not knowing that doing so would free the elder Princess Shroob and restore her power to her. It seems that Baby Luigi was the only one knowing because he cried at the Cobalt Star.

Artifacts

Artifact | Balance Stone | Beanstar | Black Chest | Black Skull | Chaos Heart | Chomp Rock | Cobalt Star | Crystal Ball | Crystal Stars | Diamond Stone | Form Baton | Grand Star | Green Power Star | Jade Raven | Lunar Stone | Magic Scepter | Magical Map | Marvelous Compass | Moon Stone | Music Key | Power Star | Pulse Stone | Pure Heart | Pyramid Stone | Red Power Star | Sacred Cylinder of Cheese | Shadow Star | Shine Sprite | Silver Star | Skull Gem | Star | Star Piece | Star Rod | Sun Stone | Treasures | Vibe Scepter | Volcano Vase

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