Tohl Narita: “I applied an image of a Japanese rhinoceros beetle to the human body. […]”
Antlar is a kaiju which appears to have a Japanese rhino beetle (called kabutomushi, armor insect, in Japanese), stag beetle and antlion put together.
Narita says he thought that the color of the design A (in this blog) didn’t look good when supposing the monster should come up from underground and he was reluctant to paint an underground creature blue (B) so he made it black and red in the end (C).
As we see Antlar partly painted blue on his back, his remark seems to be somewhat confusing, and B looks much closer to the finished Antlar costume.
Narita explains the antlers were shifted to a lower position so that it could make the battle between Antlar and Ultraman easier when grappling with each other although this explanation is also confusing because it sounds as if he talks about the shift from C to B.
It is interesting to find that the design B shows the eyes and a horn seemingly added afterwards to the design as a rhino beetle has a horn of the same shape on its head (the reshaped bottom part of the body is also shown in red ink).
Amazingly enough, the monster seems to have been plotted to have a mouth with teeth like an animal instead of the one like an insect or crustaceans seen in the show as shown in the picture below.
Antlar is said to be the first monster Ryosaku Takayama sculpted for “Ultraman” except the ones that were remodeled from other kaijus used before.