Urban legends are stories that are circulated as true, often involving horrifying or humorous elements happening to friends or family members. Common examples described in the document include Bloody Mary, where a spirit may appear in a mirror when her name is called three times, and stories of alligators living in the New York City sewer system. Urban legends are often plausible enough to be believed but are generally not factual stories. They are typically passed along through oral or written forms from person to person.