Abuse of a Brownie, either through neglect of chores, a failure to leave out food or deliberate insult, will turn it into a Boggart.
Also known as Bogans or Bogies, Boggarts delight in tormenting those they once protected and will cause milk to sour, doors to slam, dogs to go lame and other mischief.
Boggarts particularly like to steal food and to hide household items like keys and socks. More common than Brownies, Boggarts reside in many houses and workplaces. This may be the result of decades of improper treatment of Brownies, which were once far moreprevalent.
As loyal as Brownies, Boggarts are almost impossible to get rid of. Many families have fled from a house tormented by a Boggart only to find the Boggart fleeing with them.
Boggarts are sometimes confused with Polteregeists because both terrorize households. And as both generally remain unseen, it can be hard to tell the difference. Listen carefully after something goes awry; if muffled laughter is heard, a Boggart is the likely culprit. (Compare to Brownie and Hobgoblin)