EBIRAH, HORROR OF THE DEEP (a.k.a. GODZILLA VS. THE SEA MONSTER) is from 1966 and it’s the seventh Godzilla picture. The title monster is a giant lobster, and there are other members of the kaiju community involved, but the central conflict is actually unrelated to them – it’s about a fairly random group of people who stumble across The Red Bamboo (a terrorist army – like, with uniforms and everything) and use the monsters to disarm them for the sake of the world.
It happens like this. Ryota (Toru Watanabe)’s older brother Yata (Toru Ibuki, GHIDORAH, THE THREE-HEADED MONSTER)’s fishing boat was lost during a storm on the South Seas. He’s presumed dead, but Ryota thinks he’s alive because a psychic at Spirit Mountain (Noriko Honma, STRAY DOG, SEVEN SAMURAI, YOJIMBO) said so. He wants to take a boat out to the uncharted area where he thinks he’s shipwrecked, but he doesn’t have a boat, and he’s kind of a rube, so when he sees a dance marathon on TV where the grand prize is a yacht, he goes there.