“Jump the Shark” has become apart of American lexicon to describe an event that indicates something has just peaked and it’s all downhill. “Jump the shark” was coined when Happy Days went to Hollywood for three episodes.
The Fonz was challenged by Ralph to water ski-jump over a shark. Before “Jumping the Shark” Happy Days was #1… after the episode of Fonz jumping the shark, Happy days spent another SIX years as #1. But the phrase stuck and 'Jumping the Shark' is used regularly in business and entertainment.