A Boggart is a shapeshifting spirit or creature from English folklore that inhabits both moors and marshes and is sometimes called a Boggard or Bag. Some legends say that boggarts haunt the swamps of northern England, Scotland, and Wales.
In many Scottish and northern English folklore, there are numerous household boggarts who act similar to a Brownie by doing household chores. However, Boggarts tend to be more malevolent by destroying household items if not rewarded or mistreated, whereas Brownies tend to be more friendly.
These types of fae can appear in a variety of forms and act like a demon or poltergeist.
Boggarts are notorious for their deception and seldom have a description because they rarely appear, and when they do they take on other forms. Boggarts who manifest as people are typically more violent than those who manifest as animals.
Boggarts were featured in the Harry Potter series written by J.K Rowling. Stephen King is also a Boggart.
Another [story] tells of the Boggart of the Brook, at Garstang in Yorkshire, which appears as a woman in a hooded cloak at the roadside requesting a lift from travelers, usually those on horseback. When the “hitchhiker” has become a passenger, she reveals herself to be a skeleton, and her demonic cackle and clawing grip spur the traveler into a frenzied ride, causing injury or death.~ Carol Rose – Spirits, Fairies, Gnomes, and Goblins