Tohl Narita: “I drew designs like A and B (in this article) but I quit it because, as they look like Edd Cartier’s aliens, I found them unsuitable for Ultra Q. While I decided to use the design C instead, I slightly changed the ears as it is boring if it looks like a mere ape.”
Although Narita describes this way, the completed costume of M1 ended up having no such ears, and the design B was introduced as “M2” that din’t appear in the show in publications at that time.
While the M1 (C) designed by Narita looks somewhat scary, it was sculpted by Ryosaku Takayama probably with adjustments at his discretion (the same should be true of, say, Peguila) through discussions between Narita and Takayama.
I believe Takayama played a significant role in sculpting the kaijus designed by Narita while expanding the concept of each of Narita’s design drawings with his own interpretations and adjustments so that it should have enormously helped Narita-designed kaijus win such great popularity that remains unchanged even today.
I think forming each design into an actual costume in his own way is a great talent Takayama characteristically had as a painting artist while it was a great, maybe unprecedented, team play between him and Narita, a sculpting artist.
As to the costume of M1, it was made so that the actor’s eyes could be seen through the eye holes while the same method was applied to the costume of Alien Goron who appeared in “Ultraseven” (Alien Goron was allegedly sculpted by the Tsuburaya art staff).
Along with the costume, Takayama also sculpted a marionette that was used in the scene at the end of the episode.
Tetsuo Yamamura who played the shoe shine boy Itachi in this episode says in a book, “M1’s lips were soft and beautifully colored pink. It looked as if he was actually alive even with nostril hair that looked so real, and I was always clinging to M1 during standby time.”