You've heard the expression 'Jump the Shark' before, right? But do you know what it means?

It's a negative expression typically used to say that something that was once good has now peaked, and has taken a severe downturn in quality or usefulness.

We can actually thank the Fonz (Henry Winkler) on the TV show "Happy Days" for the origin of the phrase 'Jump the Shark.'

It all stems back to a 1977 episode of Happy Days, where the Fonz who was afraid to waterski was challenged to an absurd stunt of jumping a caged shark while on water-skis.

Fans of the TV show Happy Days generally believe that episode was the pinnacle of the television series. After that point, the quality of the series started to rapidly decline.

I mean really, how do you improve on something like that? You can see why the show started to tank. No pun intended.

That shark stunt episode has also become a household cultural symbol of when quality takes a dramatic downturn for the worse in daily life.

The Jump the Shark phrase was allegedly coined by a fellow named Sean J Connolly, a friend of a web publisher named Jon Hein.

Hein started a website, jumptheshark.com, which has now become a celebrity gossip hub.

Getting back to the TV series Happy Days. What's really scary, the series continued to air for another 7 years after the Jump the Shark episode. That's when a show supposedly set in the mid 50's to mid 60's, started to resemble the late 70's in appearance. Mainstay characters like Richie Cunningham (Ron Howard) and Ralph Malph (Donnie Most) started to go away. Only to be replaced by the likes of Roger Phillips (Ted McGinley) and Jenny Piccalo (Cathy Silvers).

I'd say they jumped the shark!

In case you missed that legendary Jump the Shark scene, here it is.