Boggart
The boggart is well known in Northern English forklore as a shape-shifting spirit that, while normally invisible, can materialize as a human, an animal, a skeleton, or even a demon. Most bogarts delight in frightening people. Some are merely mischievous, resembling the poltergeist in their effort to create chaos in an ordwely household. According to tradition, you know one of these meddlesome creatures is around when doors slam for no reason, candles suddenly go out, tools disappear, and Mysterious noises echo through the house. Other boggarts of a more vicious nature lurk on dark roadsides and frighten lonely travelers, sometimes causing injury or even death.
The boggart is a relative, some might say the evil twin, of the fare-more-friendly brownie. Brownies appear in England folktales as household helpers. who take great personal responsibility for the homes in which they live and bring good luck to the homeowner. They clean up messes, complete unfinished chores, make bread, harvest grain, herd sheep, and mend broken tools and cloths. In return for their labors, they are entitled each evening to a bowl of milk or cream and a piece of cake. An offer of any greater reward is taken as an insult, and brownies are easily offended and angered. When offense occurs, a boggart may appear to take the brownie's place.