Boggarts are mythical creatures from English folklore, often described as shape-shifters that can take on the form of a person's worst fear. They are typically associated with dark, damp places like bogs or marshes. Boggarts are known for their mischievous behavior, causing trouble for those who encounter them. In literature, boggarts have been popularized by works such as the Harry Potter series, where they are depicted as magical beings that can transform into whatever frightens a person most. To ward off a boggart, one must confront their fear with humor, often using a spell called Riddikulus.