“An alien aiming for the Earth transforms monsters to attack!”
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.
Ishirō Honda
Ei Ogawa
Taiichi Kankura
Akira Ifukube
Akira Kubo
Taro Kudo
Yukiko Kobayashi
Saki, native girl
Atsuko Takahashi
Ayako Hoshino
Yoshio Tsuchiya
Dr. Kyoichi Mida
Tetsu Nakamura
Chieftain Ombo
Sachio Sakai
The Editor (uncredited)
Kenji Sahara
Makoto Obata
Yū Fujiki
Promotion Division Manager (uncredited)
Noritake Saito
Rico, the guide (uncredited)
Chōtarō Tōgin
Yokoyama, an agent (uncredited)
Wataru Ōmae
Sakura (uncredited)
Yukihiko Gondō
Islander (uncredited)
... and 5 more
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....
TOHO
Toho Eizo Bijutsu
Tokyo Laboratory