Originally, the creature was going to be alien and the premise was going to be like "Predator" in the woods with hunters instead of commandos, but the writers decided "Human Season" would feature a Wendigo instead.
The Wendigo design is based off the Wampa from "Empire Strikes Back" and an original design from the writers.
The voice of the Wendigo and its roars is a combination of human vocals and the sounds of a walrus, steer, lion, bear, and tiger.