Many have noted the shark episode as the moment when they realized the show was no longer worth watching, considering the scene to be unrealistic and of poor quality, making it impossible to maintain suspension of disbelief...
More recently, the phrase has been used outside the realm of popular culture, representing anything that has reached its peak and has turned mediocre. For example, if one thinks a stock or a sports team has reached its peak, one can say that it has "jumped the shark".
My sidekick Kearns has a briefer, but no less acute definition:
The watershed moment when a tv series starts becoming shit.
So far so good. I recently found out – and bear with me if you knew this already – that the TV sitcom Mork and Mindy was actually a Happy Days spin-off show. In Mork and Mindy, wacky comic actor Robin Williams played an eccentric alien (Mork) who had been sent to Earth to study human behaviour.
Anyway, now it’s time to coin a new phrase. Happy Days jumped the shark, then gave birth to Mork and Mindy (here’s how, if you're interested). You could see jumping the shark as the initial watershed moment – or you could see it as a prelude to an even more ridiculous, far-out moment: the moment when a show "introduces an eccentric alien who looks like Robin Williams".
How can this snappy expression be used in real life? Well, let's look at the trio of Labour party scandals that occurred in April this year. One might say this:
"When Charles Clarke's Home Office deportation scandal hit, it looked like the Blair government had jumped the shark. With the Prescott affair, it introduced an eccentric alien who looks like Robin Williams."
Mark my words, that'll be in the Oxford Dictionary of Idiom next year. I wonder if my readers have any good examples of when they might use the expression? It would be good to hear from you both.