Something I once thought about is how certain fantasy/fiction monsters/creatures are basic alterations of humans like how cyclops are just a person with a single eye or how an elf is someone with pointy ears. Of course, there's interpretations that go crazier than that, but I mainly thought of this because of how in real life, the closest to a cyclop would be someone with a deformity where their 2 eyes are fused together. Because I also wonder what happens first: Someone from thousands of years ago creates a fictional monster with clear difference from humans or someone in real life is born with such abnormalities, that either inspires the fictional monster or is compared to one and even has a disease/condition named after it.

Another thing is how fictional races can still have a certain level of "natural perfection" or "rules" where, a cyclop is meant to have one eye, so they don't look the same as someone with their eyes fused into one weird eye. And it's not just a matter of art style (Like cyclop characters looking less uncanny in a stylized/cartoony art style instead of looking realistic), because even with live action, you can still make the cyclop seem natural to their own nature.

Siamese twins are a similar thing: It's not just that someone with 2 heads is unnatural, it's that most of the time, they look even weird than fictional characters with 2 heads, like how some siamese twins have one half being taller than the other. So if an artist wants and has the skill and effort: You can make a character with 2 heads that still looks "idealized" or at least natural in their own terms.

Basically, imagine if someone was born with long ears and they're said to have the "elf syndrom". But their ears are so weird looking, they're not the same as idealized, fantasy elfs whose pointy ears still look fancy.

In a way, what IS more uncanny? A guy born with one eye that looks weird because it's their 2 eyes fused together? Or a perfect real life cyclop where the single eye looks relatively normal and even functions properly?

Part of why I made this post is because I did look up other people's 2 headed characters when designing that female Hellhound for Hirdrih. But during Nortubel, when I drew the character Tfoorie, I remember watching a video of someone's cat born with 2 conjoined heads so they had 2 mouths and 3 eyes. The one eye in the middle was of course 2 fused eyes and there's even clips of both before and after the surgery to get that middle eye removed.

I think what makes multiple eyes weird is the fact that the human brain wastes more energy for the sake of extra body parts. It's almost the same reason why people that are taller than usual tend to have shorter lifespans. Even if humans are different from each other and change based on evolution and other factors, there's always some rules that makes us limited. Because one thing is people that look ugly or weird because of deformities or just poor health habits and environment. But it also means that if someone looked very beautiful/handsome and has so many traits like being tall, that could still come with a price.