In the book “The Art of Avatar: The Way of Water,” we discover that, with the gill mantle functioning like “an organic scuba apparatus,” early concepts looked a little too close to the iconic and facemask-esque facehugger early on. Creature designer Dylan Cole explains:
Jim wanted something diaphanous and beautiful. Legacy Effects did some beautiful early designs, but some looked a little too invasive, and we joked that it was too similar to the face hugger from “Alien.” And then creature designer lan Joyner was doing some cool stuff where it was starting to get a little bit more diaphanous and beautiful, almost like a piece of wardrobe.
The end design became a “ray-meets-jellyfish thing that would swim in a very sinusoidal movement,” which lead to the final gill mantle design (by Constantine Sekeris).
In its final iteration, the gill mantle became a fluid, back-mounted creature whose flowing fins appear (once attached) like a pair of water wings. This avoided the visual similarities to the facehugger, ever-clasped over a human victim’s face like a demonic Harlem Globetrotter would palm a basketball. The final mode of attachment took inspiration from the gecko, where “Jim talked about gecko feet to hold onto the ribs so that you believe that it’s latched on,” the creature sticking to its Na’vi transports as they traverse the water at high speeds.