Tohl Narita: (about Kaigyo) “As an experimental design of a kaigyo (mysterious fish), this is a design I like very much. But I was told that they would like to make an octopus appear as the script was written assuming the octopus from Toho. If the kaigyo had appeared, it would have become one of the best kaijus.”
As Narita explains in his art books, the monster to be featured in Ultra Q Episode 23 “Fury of the South Sea” was changed from the kaigyo to the giant octopus Sudar with the use of the puppet used in the 1965 Toho movie co-produced by the US company Benedict Pictures “Frankenstein vs. Baragon/Frankenstein Conquers the World.”
Incidentally, “kaigyo” represents “mysterious fish” and not the individual name of the giant fish monster (it should have been dropped before getting any specific name).
As to Surar, while scenes with a real octopus used were added, the puppet octopus also looked real as it was excellently sculpted.
A giant tentacle was sculpted by Ryosaku Takayama and was used for a scene of the tentacle attacking Manjome while the prop was also excellently sculpted.
It is said that the idea of this episode “Fury of the South Sea” can be traced back to a sample story titled “The Counterattack of Giant Octopus” covered in the first planning paper of “UNBALANCE,” the planned show that turned out to be “Ultra Q” in the end.
In “The Counterattack of Giant Octopus,” Manjome seems to have been planned to fight with the giant octopus with a supercar he boarded including fight scenes in the sea and the showdown at Haneda Airport (this sounds like sort of an off-the-wall story that makes me feel like watching it).
I have to admit I personally found it a bit disappointing to see this episode just feature a giant octopus when I was a kid, but, given how Bostang was portrayed in the show, it makes me wonder how well the kaigyo could have been depicted with techniques of the time although the design variations Narita drew make me fully aware that he should have put a lot of energy into designing it while I find his kaigyo attractive enough.