Koopook

Koopook is a Koopa that is hidden somewhere in Hooktail Castle during Paper Mario: The Thousand-Year Door. Mario must accept his trouble first at the Trouble Center. But Mario needs to search everywhere to find him. When you do he will give you your reward. He will also mention how he got there and his relationship to Koops.

The reward is the Airplane game card you can use at Pianta Parlor to play it. If you get a high score on the game, Lahla will tell you more about herself and family. Later on in the game, Mario will get an e-mail from him saying he has hidden in a different spot and he may try to find him again. He says he will give Mario another reward even if he is working on somebody else's trouble at the time. This is not possible in the game because Koopook is hiding in the Crystal Palace, an area unaccessable in Paper Mario: The Thousand-Year Door.