The Giant Gila Monster

When Dr. Frankenstein is killed by a monster he created, his daughter and his lab assistant continue his experiments.

Dracula conspires with a mad doctor to resurrect the Frankenstein Monster.

Brilliant but arrogant scientist Victor Frankenstein builds a man from spare body parts, only for the monster to come alive and wreak havoc.

Gaira, a humanoid sea beast spawned from the discarded cells of Frankenstein's monster, attacks the shores of Tokyo. While the Japanese military prepares to take action, Gaira's Gargantua brother, Sanda, descends from the mountains to defend his kin. A battle between good and evil ensues, leaving brothers divided and a city in ruins.

During WWII, Germans obtain the immortal heart of Frankenstein's monster and transport it to Japan to prevent it being seized by the Allies. Kept in a Hiroshima laboratory, it is seeming lost when the United States destroys the city with the atomic bomb. Years later a wild boy is discovered wandering the streets of the city alone, born of the immortal heart.