Xanthophobia is a fear of the color yellow or anything that might involve the concept of yellow. I can't say that yellow is my favorite color, but it's very nice for certain things. But a fear? Seems silly to me, but the world is filled with a lot of silly seeming things...
Xenomorphs are not something that might ring a bell with a lot of us from the term, but if you've seen those films in the Alien franchise or similar types of films then that big ugly creature is what I'm talking about. In the original Alien (1979) by Ridley Scott, the creature was imagined by artist H.R. Giger, a sci-fi surrealistic artist from Switzerland. Giger has designed creatures for many films as well as doing the artwork for many album covers. He has done some wild imaginative work, but those creatures have been terrifying.
Looking at one of those dark fearsome xenomorphs I can imagine that they don't like bright things and that probably especially goes for bright colors like yellow. I might venture to guess that a xenomorph might even have something like a fear of the color yellow. If anyone or anything might display indications of xanthophobia it might be a xenomorph.
And in this age of reproducing things and cloning, what if we were to start duplicating xenomorphs? It would in essence be like xeroxing xanthophobic xenomorphs.
Are you a fan of the Alien movie franchise? Do xenomorphs frighten you? Is yellow a color that you like a lot or not so much?