Chopper's Kingdom on the Island of Strange Animals is the third animated feature film of the franchise and the first to additionally star Ikue Ohtani as Tony Tony Chopper. It premiered in Japan on March 2, 2002 and was released to DVD on October 21, 2002.The film was shown in a double bill with Digimon Tamers: Runaway Locomon. Starting with their first week of showing, the films made a six weeks run in the Top 10 of the Japanese box office, placing third in the first two weeks, fifth and fourth in the third and fourth weeks, respectively, and sixth in the fifth and sixth weeks.In total, they earned 2,000,000,000 Japanese yen, according to the Motion Picture Producers Association of Japan and 13,107,237 United States dollar, according to Box Office Mojo.The film was show along with a six-minute featurette short named Dream Soccer King!.
With Chopper as their newest member, the Straw Hats arrive at the Island of Strange Animals. Before they can land, a geyser-like fountain sends their ship flying. Chopper falls off and lands in the middle of a gathering of animals. They are performing a ritual, which according to their legend, is supposed to cause a king to fall from the heavens. Believing that legend fulfilled, they proclaim Chopper their new king. The other Straw Hats, searching for their lost crewmate, make the acquaintance of the self-proclaimed genius and expert treasure hunter Count Butler, with his henchmen General Hot Dog and President Snake. Butler is in search of the horns of a particular animal living on the island, which when eaten bestows great power upon the eater. For that purpose, he uses a hoard of bovinae-like animals called horn eaters, which he controls by playing music on a special violin, to round up horn bearing animals. The Straw Hats, unknowingly, lead Butler to Chopper and the group of animals, whose king he has become. Butler gives the gathered animals an ultimatum, to hand over their king, whose horns he believes to be what he is looking for, or to be crushed by his horn eaters. But Chopper does not need to be turned over. He steps forward himself and lures the horn eaters away from the island's animals. A fight ensues and it does not take long until the remaining Straw Hats join in to take their fill. Zoro takes on Hot Dog and Sanji fights with Snake, while Usopp and Nami take care of the horn eaters. Butler fights with Chopper and is about to finish him off, when Momambi, a young boy and only human inhabitant of the island shows up with the former king's horns to lure Butler away from Chopper. The plan backfires, as Butler gets hold of the horns, quickly stuffs them down, and transforms into a large, horned, gorilla-like animal. With that he appears to be winning, until the islands animals and Luffy enter the fight. Luffy defeats Butler, breaks his horns, thus canceling his transformation, and sends him flying. Mobambi fears to be exiled from the island for losing the former king's horns, but instead is elected to be the new animal king.