Tony Tony Chopper is the doctor of the Straw Hat Pirates. A reindeer who ate the Human-Human Fruit (Hito Hito no Mi), this Zoan-type Devil Fruit granted him human intelligence, speech, and transformation abilities. He shifts between his natural reindeer form, a human-reindeer hybrid form (his typical appearance), and a fully human form. In his hybrid form, he stands about 90 centimeters tall with brown fur, a distinctive blue nose, and antlers; his left antler has a metal brace from a past injury. He wears a pink top hat adorned with a medical cross symbol, a gift from his surrogate father, Dr. Hiriluk. Born with a blue nose, Chopper faced rejection from his reindeer herd. After consuming the Devil Fruit, his herd further ostracized him for his human traits. Humans on Drum Island also feared him, attacking him as a yeti. Dr. Hiriluk rescued him, named him, and became his surrogate father, teaching him that all diseases are curable and the Jolly Roger represents resilience. Following Hiriluk's death, Dr. Kureha trained Chopper in medicine for five years. During this time, he developed the Rumble Ball, a drug granting temporary additional transformations beyond his standard three; misuse could trigger a dangerous, uncontrollable Monster Point form. His medical expertise covers surgery, pharmacology, and creating antidotes. As the crew's doctor, Chopper treats injuries and illnesses. He displays naivete, often believing exaggerated stories, and reacts with flustered denials when complimented, though secretly enjoying praise. He angrily corrects those who mistake him for a tanuki, insisting he is a reindeer. A deep-seated fear of being perceived as a monster stems from his past ostracization. He maintains a childlike enthusiasm for adventure and can communicate with other animals due to his reindeer nature. During "The Giant Mechanical Soldier of Karakuri Castle," Chopper is present when the Straw Hats rescue an old woman from a sinking ship. She promises the legendary Golden Crown treasure on Mecha Island. Upon arrival, the crew faces attacks from the island's defenses and its ruler, Ratchet. Chopper repeatedly hears a mysterious voice calling out, which he alone perceives. This voice emanates from the island itself, revealed to be a giant turtle. Chopper's ability to hear and understand the turtle is crucial to uncovering the island's secret nature. He participates in solving riddles related to the Golden Crown legend, detailed in the "Yurari Uta" folk song. After the turtle island awakens and Ratchet attempts to seize control with his mechanical castle, Chopper learns the turtle awakens every 1000 years to lay eggs. He witnesses the hatching of an egg and the revelation that the Golden Crown refers to the golden fragments of the turtle's eggshell; the crew ultimately loses their acquired fragment. His combat abilities utilize transformations: Brain Point (small hybrid for thinking), Heavy Point (large muscular humanoid for strength), and Walk Point (reindeer for speed). The Rumble Ball enables temporary forms like Kung Fu Point and Horn Point. While Monster Point was a dangerous last resort pre-timeskip, subsequent training allowed limited control. Specific combat transformations in the film are not detailed, though he participates in the crew's efforts against Ratchet's forces.