Space Amoeba (ゲゾラ・ガニメ・カメーバ 決戦! 南海の大怪獣, Gezora, Ganime, Kamēba: Kessen! Nankai no Daikaijū, lit. 'Gezora, Ganimes, and Kamoebas: Decisive Battle! Giant Monsters of the South Seas') is a 1970 Japanese kaiju film directed by Ishirō Honda, written by Ei Ogawa, and produced by Tomoyuki Tanaka and Fumio Tanaka, with special effects by Sadamasa Arikawa. Produced and distributed by Toho Studios, the film stars Akira Kubo, Atsuko Takahashi, Yukiko Kobayashi, Kenji Sahara, Yoshio Tsuchiya, and Yu Fujiki, with Haruo Nakajima portraying both Gezora and Ganimes.

Space Amoeba tells the story of an alien amoeba that hijacks a space probe and, after crash landing on an atoll in the Pacific Ocean, creates gigantic monsters from native lifeforms (a kisslip cuttlefish, elbow crab and mata mata) for the purpose of conquering the Earth. The film was released theatrically in Japan on 1 August 1970, and received a theatrical release in the United States in 1971 by American International Pictures, under the title Yog: Monster From Space.