Even though Robert Dunham spoke nearly perfect Japanese throughout most of the film, he did get away with one phrase of English. In the scene where the mob breaks into his hotel room and Hamako (Moll) snatches the key to the safe, he says in perfect English, "Hey, you can't take that!"
Dogora is the one of the few Toho monsters that doesn't appear in a Godzilla film. However, the creature does appear as a still shot in the opening of the 2017 anime movie "Godzilla: Planet of the Monsters."
Dogora was portrayed with a soft vinyl prop placed in a large tank of water and manipulated with a mixture of fishing line as well as the flow of water from a valve fixed at the bottom of the tank.
There were originally plans to feature Robert Dunham in a series of films based on the "Mark Jackson" character he played in this film. However, those plans never came to fruition.
Suit-maker and prop designer Keizô Murase developed the idea to create the Dogora prop out of soft vinyl, which had only recently come into the market and was quite costly. While the Dogora prop would prove quite expensive, Eiji Tsuburaya would ultimately approve of Murase's decision.