<P> The idiom "jumping the shark" is pejorative, most commonly used in reference to gimmicks for promoting entertainment outlets, such as a television series, that are declining in popularity . </P> <P> Originally the phrase was used to describe an episode of a television comedy with a gimmick or unlikely occurrence desperately attempting to keep viewers' interest . Moments labelled as "jumping the shark" are considered indications that writers have exhausted their focus; that the show has strayed irretrievably from an older and better formula; or that the series as a whole is declining in quality . </P> <P> Popularized by radio personality Jon Hein in the 1990s and early 2000s, the phrase derives from a scene in a fifth - season episode of the sitcom Happy Days in which the character Fonzie jumps over a shark while on water - skis . This was deemed a ratings ploy, for it was outside the original thrust of the sitcom . </P> <P> The usage of "jump the shark" has subsequently broadened beyond television, indicating the moment when a brand, design, franchise, or creative effort's evolution declines, or when it changes notably in style into something unwelcome . </P>

Where did the phrase jump the shark come from