Tony Tony Chopper

Tony Tony Chopper is the doctor of the Straw Hat Pirates. Chopper is a reindeer that consumed the Devil fruit, Hito Hito no Mi. He comes from Drum Island, which makes him the only member of the Straw Hat Pirate Crew who was born on the Grand Line. He is the sixth member of the crew and the fifth to join, as well as being the youngest member on board. He ate the Hito Hito no Mi, or the 'Human-Human Fruit' when translated.

Appearance
Most of the time, Chopper is a toddler-sized human/reindeer hybrid, but his Devil Fruit abilities allow him to change his appearance depending on the situation. Chopper's left antler has a metal plate wrapped around it at all times, from being broken in a fight when he was younger. The usual clothing he wears includes a pale red/pink, fuzzy top hat with a sideways medical cross (given to him by Hiluluk) and a maroon pair of shorts. He also sometimes wears a blue backpack that has the same sideways medical cross as his hat. Chopper also has a remarkable feature that no other reindeer have, a blue nose, while normal reindeers have black ones. As Oda's style evolved, Chopper has been given a more "chibi" appearance, meaning that when in his Brain Point, Chopper has a larger head and eyes.

Chopper wears different outfits just as any other character in the crew.

In Alabasta, he wore a shirt with a green-lined collar, then a bigger one with giant sleeves that is light blue with dark blue liners.

At Enies Lobby, he wore a red leather jacket.

A running gag is that various characters in One Piece think Chopper is a tanuki (raccoon-dog, often simply translated as "raccoon") whilst in his Brain Point form. This is a play on the similar word "tonakai," the Japanese word for reindeer, from which the "Tony" in Chopper's name is derived. His heavy point form likewise is mistaken for a gorilla or an abominable snowman.

Many female characters, such as Nami, Robin, and Porche, find Chopper very cute.

Oda has stated that he uses the color pink to represent Chopper, he enjoys spring on a winter island, his favourite foods involve cotton candy, chocolate and other sweet food and drinks, he would be the youngest son, if he were real his nationality would be Canadian, and (Oda was answering the questions as Chopper) for his smell it would be sugar and medical supplies. The flower that best suits Chopper is the tulip.

After the two-year time skip, Chopper wears a new blue and pink cap about the same size as his old pink hat. The X has a white circle surrounding it, and a ring of dots around the circle, while the cap has buckles hanging from it. He also wears a white and yellow vertical-striped tank top and a orange pair of shorts. Chopper's Brain Point form has changed little, aside from being slightly slimmer. His Walk Point form has grown considerably, now being roughly as tall as Usopp. His horns are larger, he has more muscle, and his fur is longer. His Heavy Point has not been shown. He was recently shown to have developed a new form during the timeskip, Kung Fu Point, which he used to defeat King Neptune's soldiers.

source: onepiece.wikia.com