A skinwalker, yee naldlooshi, or Navajo witch is a type of shapeshifter which has recently become a fixation of /x/. Skinwalkers are a type of witch capable of changing into an animal, which in some legends requires wearing a pelt of the animal.
Most skinwalkers are assumed to follow the Witchery Way: to become initiated, you must kill a close relative. A sibling, a parent, a son or daughter. This Way is based around poison - of the mind and body, using both the powdered bones of the dead (where the initiation comes in) and dark rituals.
Once initiated, the witch is a skinwalker. They can take on the form of any animal they choose, usually through donning its skin but research shows that it is not a requirement. Anyone can become a skinwalker if they have a lack of morals and a hunger for power. Becoming a witch is bad enough, but the skinwalkers are more powerful and more feared.
To curse someone a witch (already initiated) would take a personal effect or another kind of taglock, then bury them with the flesh of the dead, then sing a "prayer" - usually an inverted prayer, a normal prayer sung backwards or otherwise altered. As can be seen, the initiation serves several practical benefits as well as the simple initiation as one body will last a witch a long time.