Gappa, the Triphibian Monster (1967)

In 'Gappa, the Triphibian Monster,' a pair of prehistoric creatures are discovered on an isolated island and are brought to Japan as attractions. The monsters, Gappa, are separated from their offspring and go on a destructive rampage to find their baby. As the military tries to contain the chaos, a family risks their lives to reunite the creatures and return them to their home. (Note: 'Gappa, the Triphibian Monster' is a Kaiju film with a storyline similar to other monster movies of the time.)