Appalachian culture greatly influences its short fiction. The strong sense of community in Appalachia is often reflected in the stories, with characters relying on one another. The folk traditions, like music and storytelling around the fireplace, find their way into the fiction as well.
I don't have a definite answer for you. The Mimic might be based on a combination of folklore, myths, or the author's imagination. It's hard to pin down a specific source.
Well, 'the mimic ghost story' could potentially revolve around a haunted place where a ghost has the ability to mimic. Maybe it mimics the appearance of someone you know to lure you into a dangerous situation. It could also be a story of a vengeful spirit that uses mimicry as a form of torment for the living.
Once upon a time, there was a mimic spirit in a forest. It could take on the forms of various things it saw. One day, it saw a beautiful woman. It was so fascinated that it decided to transform into a woman. It mimicked her every feature, from her long flowing hair to her graceful walk. And so, it became a woman - like figure, living among the trees, sometimes scaring the local villagers who thought it was a real woman but with an otherworldly air.