Tohl Narita: (about Balloonga) “I didn’t come up with any other idea for a monster that inflates in the sky than this.” (about the other drawing for an episode with the title “Endless”) “This is a story that was not produced, but, just Balloonga, I had no choice but to draw a design like this in attempts to expand the story.”
I personally like Balloonga as an attractively strange monster along with Bullton. While it is said to have been sculpted by Akira Sasaki, he himself says he doesn’t remember at all having made the monster (prop).
It seems to be said the prop was brown just as raw rubber, the material the prop was made of, was, and it is likely that Hiroko Sakurai who played Yuriko Edogawa in “Ultra Q” (Akiko Fuji in “Ultraman”) remembers it was brown with a dirty look.
There is an explanation that there was another prop painted red for optical compositing.
The other design (above) drawn by Narita was an unnamed monster that was supposed to appear in an episode titled “Endless (Kiriganai)” although the Ultra Q episode ended up being left unproduced.
The episode was written by the director Akio Jissoji under the pseudonym of Yuri Manpukuji and was to be directed by himself, but, according to a book Jissoji authored, it was rejected in the end as the monster was to come back to life endlessly.
It seems that it was an amorphous monster that appeared in the sky above a dam in Tokyo absorbing water, which caused a severe water shortage.
Although people destroyed the monster by removing water from the dam, it was set to restore itself perpetually (probably absorbing any moisture in the atmosphere).
It sounds like such a crazy story as it is so Jissoji.