These shows didn't "jump the shark." That doesn't do them justice.
No, these are shows where the creators simply said "fuck it", flew out of the water, broke the bounds of the earth's atmosphere and set a course for the center of the Sun.
They took their shows down in a blaze of batshit insane glory, and we were there to watch.
Specifically, we're referring to a spinoff many of you didn't know existed, called Baywatch Nights. Judging from the title and David Hasselhoff's fondness for not trying too hard, you'd think this show would be Baywatch, at night. Instead they took the extra step and made it Baywatch, only in a detective agency solving beach cases. But if you watch it in slow motion with the brightness turned down, yeah, it's Baywatch, at night.
Basically the premise is that the main police officer on the original Baywatch show, Sergeant Garner Ellerbee--and yes, that was his actual name on the show--has a midlife crisis and quits his job to start a detective agency. He's joined by Mitch Buchannon, grippingly portrayed by nuanced character actor David Hasselhoff.
Together, they solve beach-related crimes, every week. Loitering-related murder came up a lot. Eh, we've heard worse ideas for shows...
So, What Happened?
It got "X-Filed."
Baywatch Nights didn't turn into the mega-hit its predecessor was, and producer/star David Hasselhoff wanted a piece of all the money X-Files was making at the time. So, he started forcing a science-fiction plot into every single episode. You would think that they would run out of sci-fi beach crime plots quickly, and... they did.
And thus some of the most ridiculous plots ever aired on TV were born. Episodes included:
A mutant mermaid serial killer;
David Hasselhoff getting cloned to save himself from mutated Brazillian-body-snatching snails.
That transition from "shitty" to "pants-shittingly shitty" happened between season one and two, and is best evidenced by the difference in opening themes. Season One:
A very standard issue shitty TV action show intro. Notice the near omni-presence of a Miami Vice suit-wearing David Hasselhoff...
There are beaches, hot people running in slow-ass mo' and boobs jiggling.
That is a winning formula, so to mess with it they must have had something nut-burstingly awesome in mind. Season Two:
Holy shit! Why is it screaming at us?
Hasselhoff switched from a comforting white-and-black Don Johnson suit to an ominous trenchcoat. Then, it's all candles and skulls...
...and, uh, taxidermy dogs.
At one point, Eddie Cibrian points a gun at the screen in what is likely an attempt to put the viewer out of their misery.
It all ends with history's most disturbing shot of Hasselhoff eye-fucking the shit out of the camera.
Viewers around the world rapidly turned off their televisions and promptly had them cleansed by an exorcist. Baywatch Nights was canceled after the second season.