The sequel to this film is The War of the Gargantuas (titled Furankenshutain no Kaijû: Sanda tai Gaira in Japan). In said film, pieces of Frankenstein's cells mutate into two giant humanoid monsters: Sanda (the Brown Gargantua) and Gaira (the Green Gargantua). The former is a benevolent and peace-loving creature, the latter is murderous and savage. Apart from a reference to a severed hand, the US co-producers ( United Productions of America ), obscured all references to Frankenstein in the American version, possibly because the two monsters could not be recognized as "Frankenstein" monsters. Gaira and Sanda would later appear in two of Toho's Tokusatsu series, Ike! Godman and Ike! Greenman , before remaining absent for over 40 years, with Gaira making his latest appearance in a 2008 Ike! Greenman special.
Judith Fontaine (Regina Carrol) is looking for her sister Joanie, who has disappeared into the hippie community of Venice, California. It turns out Joanie has become the victim of Groton (Lon Chaney Jr.), an axe-wielding homicidal maniac working for Dr. Durray (J. Carrol Naish), who is really the last of the Frankensteins and is now running a house of horrors by the beach and is performing experiments on Gorton's victims. One night Count Dracula (Zandor Vorkov) visits the doctor, showing him the original Frankenstein creation that was buried in a nearby graveyard. The doctor revives it and uses it to take revenge on his professional rivals. Written by Jeremy Lunt <[email protected]>