A cautionary tale is a tale told in folklore, to warn its hearer of a danger. There are three essential parts to a cautionary tale, though they can be introduced in a large variety of ways. First, a taboo or prohibition is stated: some act, location, or thing is said to be dangerous. Then, the narrative itself is told: someone disregarded the warning and performed the forbidden act. Finally, the violator comes to an unpleasant fate, which is frequently related in expansive and grisly detail.
Cautionary tales are ubiquitous in popular culture; many urban legends are framed as cautionary tales: from the lover's lane haunted by a hook-handed murderer to the tale of a man who shot a cactus for fun only to die when the plant toppled onto him. Like horror fiction, generally the cautionary tale exhibits an ambivalent attitude towards social taboos. The narrator of a cautionary tale is momentarily excused from the ordinary demands of etiquette that discourages the use of gruesome or disgusting imagery because the tale serves to reinforce some other social taboo.
Cautionary tales are also frequently utilised to spread awareness of moral issues, and for this reason are often told to children to make them conform to rules that either protect them or are for their own safety.
Those whose job it is to enforce conformity therefore frequently resort to cautionary tales. The German language anthology, Struwwelpeter, contains tales such as "Die gar traurige Geschichte mit dem Feuerzeug" (The Dreadful Story of Pauline and the Matches); it is fairly easy to deduce the ending from the title. Social guidance films such as Boys Beware or Reefer Madness are deliberately patterned after traditional cautionary tales, as were the notorious driver's education films (Red Asphalt, Signal 30) of the 1960s, or military films about syphilis and other sexually transmitted diseases. The framework of the cautionary tale became a cliché in the slasher films of the 1980s, in which adolescents who had sex, drank alcoholic beverages, or smoked marijuana inevitably ended up as the victims of the serial killer villain.