"In Native American legend a skin-walker is a most foul creature, a witch. By committing a cultural taboo, usually killing a member of their own family, a witch can become a skin-walker. This ability allows them to be able to transform themselves into animals, mimic voices, and place curses on towns and people."
r/Skinwalkers compiles stories, encounters, and discussions about skin-walkers.
Recommended story: Real Navajo Skinwalker Story.