Crystal Stars

The Crystal Stars serves as the main collection item needed in Paper Mario: The Thousand-Year Door.

Diamond Star
Found at Hooktail's castle, it was held by Koop's father when he was swallowed up by Hooktail, after Mario acquires the Diamond Star, he learns Earth Tremor.

Emerald Star
Treasured by the Punis, the Puni Elder gives the star to Mario after he defeats the X-Nauts, Mario learns Clock Out after taking the star.