Tohl Narita: (about Alien Bell) “I got the idea from the spider.” (about Gumonga) “I wanted to make a spider with a transparent plastic shell on its back through which you can see inside.”
It is said that Alien Bell‘s face was based on the cricket insect while it is also pointed out that the yellow part in the center is shaped like a round jingle bell.
As the alien is made with a weird design in a way, Shinichiro Kobayashi known as the kaiju morphologist (he is actually a dentist) says in a book the design lacks necessity while guessing Narita might have wandered about his design at that time.
Tetsuo Yamamura says he saw the transparent part of the alien’s head was smashed up by Koji Uenishi, the original Ultraseven actor, with his gutsy performance when the fierce battle scene between Alien Bell and Ultraseven was being filmed. Yamamura recalls Uenishi never cut corners in playing Ultraseven and always performed the hero in earnest.
In the preparatory script, it seems that Alien Bell was set to speak human words to explain the purpose of the mock space he formed in the sky so that Amagi and Soga were trapped there describing the two men as experimental materials to see if earthlings are suitable as their food.