From the Super Mario Wiki
This article is about one of the Crystal Stars. For information about the seven Crystal Stars as a whole, see Crystal Stars
The Crystal Star is the final Crystal Star in the game Paper Mario: The Thousand-Year Door. It is found in X-Naut Fortress and is guarded by Lord Crump and powers the new and improved Magnus Von Grapple 2.0. It was originally in Rogueport where it was kept in a box. Grodus took this Crystal Star with the help of Beldam, and gave it to Crump, so Mario and company had to fight him to get it. This Crystal Star will teach Mario the move Supernova, which costs six SP. To use this move, the player must simply tap the button as fast as possible to rack up damage. If performed perfectly, it will cause fifteen HP damage to every enemy on the screen.
- Despite the fact that it was originally in Rogueport, it appears in Fahr Outpost during the battle with the Shadow Queen. The reason for this is unknown.