Space Amoeba
ゲゾラ・ガニメ・カメーバ 決戦!南海の大怪獣 (original)
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.
Starring Akira Kubo, Yukiko Kobayashi, Atsuko Takahashi, Yoshio Tsuchiya, Tetsu Nakamura, Sachio Sakai, Kenji Sahara, Yū Fujiki, Noritake Saito, Chōtarō Tōgin
It's a action & adventure and science-fiction movie, and has a rating of 5.3 out of 10 from Imdb which is fairly okay for this kind of movie.
Watch it here
Not found streaming from United Kingdom.