Ashes and ashes usually appeared in novels, movies, anime, and other fictional works as a way to describe the disappearance of objects and characters. In the real world, the disappearance of objects or people could usually be explained by the laws of physics, such as the effect of gravitational fields or explosions.
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.