Gappa the Triphibian Monster (1967)

On a serene paradise island, untouched by modern technology, a modern secret lies undisturbed for centuries. Then a greedy land developer begins his plan to turn the sleepy island into the largest amusement park in the world. He sends a group of scientists to the island and they stumble across what appears to be a baby dinosaur. Opposing the terrified natives who ask them not to disturb their God, Gappa, the crew brings their new find back with them to Tokyo, and all hell breaks loose!