jump the shark
- When a once-successful TV show has a ridiculous episode that marks its turning point into being a terrible show, this is an example of a time when the show jumps the shark.
- When a successful business has a moment that marks the turn from profitability to loss, this is an example of a time when the show jumps the shark.
(third-person singular simple present jumps the shark, present participle jumping the shark, simple past and past participle jumped the shark)
From "Hollywood (Part 3)", a 1977 episode of the TV series Happy Days, in which the character Fonzie jumped over a shark on waterskis, after which (supposedly) the show bore no similarity to its original form.