Pokémon the Movie: Diancie and the Cocoon of Destruction (ポケモン・ザ・ムービーXY 「破壊の繭とディアンシー」, Pokemon Za Mūbī Ekkusu Wai "Hakai no Mayu to Dianshī", lit. "Pokémon the Movie XY: Diancie and the Cocoon of Destruction") is a 2014 Japanese animated fantasy adventure film, the 17th in the Pokémon franchise created by Satoshi Tajiri and produced by OLM, and the first in the XY series. Directed by Kunihiko Yuyama and written by Hideki Sonoda, the film stars the voices of Rica Matsumoto, Ikue Ōtani, Mayuki Makiguchi, Yūki Kaji, Mariya Ise, Megumi Hayashibara, Shin-ichiro Miki, Inuko Inuyama, Marika Matsumoto, Reiji Nakagawa, Shoko Nakagawa, Rika Adachi, and Kōichi Yamadera. In the film, Diancie, a Pokémon who is the Princess of an underground kingdom, joins the Pokémon trainer Ash Ketchum and his friends, Pikachu, Serena, Clemont, and Bonnie on a journey to meet the Legendary Pokémon Xerneas, who will awaken the power in Diancie to create a source of energy that will save the kingdom.

It was released in Japanese theaters on July 19, 2014. An English dub of the film was produced by DuArt Film and Video, and stars the voices of Sarah Natochenny, Haven Paschall, Michael Liscio Jr., Alyson Leigh Rosenfeld, Michele Knotz, Carter Cathcart, Caitlin Glass, Pete Zarustica, Brittney Lee Hamilton, Lianne Marie Dobbs, and Marc Thompson. It premiered in Australia and in New Zealand in theaters on November 8, 2014, and also aired in the United States on that date on Cartoon Network.