In the Pilot episode of The Fifth Kind, we take a look at an American monster. One that has had its story told for generations. The Wendigo was created when a human resorted to eating human flesh to stay alive. That decision came with a curse. A curse to wander the land, always hungry, never truly satisfied. 

Sources:

http://www.unexplainedmonsters.com/wendigo/wendigo_psychosis.html

https://www.legendsofamerica.com/mn-wendigo/

https://en.m.wikipedia.org/wiki/Wendigo