Gamera vs. Viras

Gamera vs. Viras (1968) is a adventure, action, science fiction directed by Noriaki Yuasa rated 5.6/10.

As alien invaders plot to conquer the Earth, two Boy Scouts steal a mini-submarine and discover Gamera in their midst. Transported to the alien's spaceship, the Scouts are menaced by the evil inhabitants, including Viras, a squid-like monster that grows to colossal size to battle Gamera.