A running gag, or running joke, is a literary device that takes the form of an amusing joke

Joke

A joke is a phrase or a paragraph with a humorous twist. It can be in many different forms, such as a question or short story. To achieve this end, jokes may employ irony, sarcasm, word play and other devices...

 or a comical

Comedy

Comedy , as a popular meaning, is any humorous discourse or work generally intended to amuse by creating laughter, especially in television, film, and stand-up comedy. This must be carefully distinguished from its academic definition, namely the comic theatre, whose Western origins are found in...

 reference and appears repeatedly throughout a work of literature

Literature

Literature is the art of written works, and is not bound to published sources...

 or other form of storytelling

Storytelling

Storytelling is the conveying of events in words, images and sounds, often by improvisation or embellishment. Stories or narratives have been shared in every culture as a means of entertainment, education, cultural preservation and in order to instill moral values...

.

Running gags can begin with an instance of unintentional humor

Unintentional humor

Unintentional humor is the act of making other people laugh without actually meaning to. There are several different kinds of unintentional humor that arise out of various situations.-Unintended contradiction:...

 that is repeated in variations as the joke grows familiar and audience

Audience

An audience is a group of people who participate in a show or encounter a work of art, literature , theatre, music or academics in any medium...

s anticipate reappearances of the gag. The humor in a running gag may derive entirely from how often it is repeated, the (in)appropriateness of the situation in which the gag occurs, or setting up the audience to expect another occurrence of the joke and then substituting something else (bait and switch). Running gags are found mostly in television shows

Situation comedy

A situation comedy, often shortened to sitcom, is a genre of comedy that features characters sharing the same common environment, such as a home or workplace, accompanied with jokes as part of the dialogue...

, but also appear in other places, such as video games, film

Film

A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...

s, book

Book

A book is a set or collection of written, printed, illustrated, or blank sheets, made of hot lava, paper, parchment, or other materials, usually fastened together to hinge at one side. A single sheet within a book is called a leaf or leaflet, and each side of a leaf is called a page...

s, and comic strip

Comic strip

A comic strip is a sequence of drawings arranged in interrelated panels to display brief humor or form a narrative, often serialized, with text in balloons and captions....

s.

A running gag can be verbal or visual and may "convey social values by echoing belligerent speakers with a barrage of caricatured threats." (e.g. - A character may present others with a proposition that is so ridiculous or outrageous it is likely to be self-mocking to the point where the original request has little or no chance of actually being carried out and results in a humorous effect.) Occasionally, the characters themselves may be aware of the running gag and make humorous mention of it.