When a space probe crash-lands on a far-flung Pacific atoll, the craft's alien stowaways decide to take over their new world one creature at a time. Soon, the parasitic life forms latch onto three indigenous critters -- a squid, a crab and a snapping turtle -- and transform them into colossal mutant monsters.
Akira Kubo
as Taro Kudo
Yukiko Kobayashi
as Saki, native girl
Atsuko Takahashi
as Ayako Hoshino
Yoshio Tsuchiya
as Dr. Kyoichi Mida
Tetsu Nakamura
as Chieftain Ombo
Sachio Sakai
as The Editor (uncredited)
Kenji Sahara
as Makoto Obata
Yū Fujiki
as Promotion Division Manager (uncredited)
Noritake Saito
as Rico, the guide (uncredited)
Chōtarō Tōgin
as Yokoyama, an agent (uncredited)
CinemaSerf
This is certainly not one of Ishiro Honda's better efforts; but it does kind of work. Some would-be alien invaders hitch a ride on a probe returning to the Earth that lands on a Pacific atoll. They set about creating supersized monsters bent on humanity's destruction so they can take over the world....