"Villain of the week" (or, depending on genre, "monster of the week", "freak of the week" or "alien of the week") is a term that describes the nature of one-use antagonists in episodic fiction, especially ongoing American genre-based television series. As many shows of this type air episodes weekly at a rate of ten to twenty new episodes per year, there is often a new antagonist to forward the plot of each week's episode.