I'm a huge UFO buff and wanted to give my own twist to this well known design. The challenge was that it's such a simple look an yet it's so much part of our pop culture that you go too far and it might not look like a grey already. Therefore being subtle with this was really important to me.
About it's biology: I imagined that not only its eye can move within the sockets, but the surrounding tissue is also two movable separated panel from the skull. The gland sacks at the two sides of it's neck might be natural, or biologically engineered additions for it to be able to adapt to different atmospheres.
Thanks for looking!