Movie
Description
Tony Tony Chopper boards an apparently abandoned ship with Usopp during the events of "One Piece 3D: Straw Hat Chase." They discover the critically ill pirate Schneider, coughing up blood. Fulfilling his role as doctor, Chopper assists in transporting Schneider back to the Thousand Sunny for medical treatment.

Chopper later joins the crew's pursuit of a bird carrying Luffy's missing straw hat. After Schneider regains consciousness aboard the Sunny, Chopper learns Schneider’s backstory: Schneider deliberately sent away his only companion, the dog Buzz, by assigning him the impossible task of stealing Luffy’s hat to spare Buzz from witnessing his apparent impending death. Chopper deduces the bird carrying the hat is Buzz, who consumed the Tori Tori no Mi, Model: Eagle Devil Fruit, gaining avian transformations.

Chopper relays this information to Schneider, revealing they are on Luffy’s ship. Schneider urgently commands the Sunny to pursue Buzz. Amidst the ensuing chaos, Chopper finds a fork on the ship’s deck. He identifies this fork as the source of Schneider’s illness – it pierced Schneider’s stomach after being accidentally swallowed while eating spaghetti, causing internal bleeding and the coughing fits mistaken for a fatal disease. Chopper’s medical expertise leads to Schneider’s recovery.

Following the conflict's resolution and the retrieval of Luffy’s hat, Chopper and the Straw Hats return Schneider and Buzz to their own ship before departing. Chopper’s actions consistently reflect his medical dedication, including treating Schneider and identifying the true cause of his ailment.