As to the body of Dada, a black wet suit was painted into a zebra pattern by spraying white paint on it while being masked with tapes so that the black parts could be left out.
The face of Dada specified as “Dada A” damaged by the shot of Ultraman’s Spacium Beam was apparently portrayed using an additional face with scars and burns whose eye parts left open attached onto Dada A’s face that remained intact.
As Dada appears to have been one of Narita’s favorite characters, chances are the alien had been newly illustrated by Narita as his art works (without the okappa hairdo) in later years.
While Dada is one of my favorites as well and I like this episode with a mysterious touch also featuring Ultraman who was shrunk to the human size, it was a bit shame that the mysterious alien made himself look so weak as to be defeated even by Captain Muramatsu!
Come to think of it, the scene where Ultaman turned human-sized was somewhat misleading to us when we were children, and there were kids including me who wrongly took it as Dada’s attack by his Micronizer took no effect on Ultraman and as Ultaman reduced his size of his own accord to try to catch or fight with human-sized Dada.
It caused us to mistakenly think of both Ultraman and Ultraseven as aliens who could adjust their sizes freely. I assume there should still be people who are mistaken about it even now except ardent fans of Ultraman as they would say, “I dimly remember I have seen Ultraman also shrink to the human size in an episode.”