Doug Wildey's "Jonny Quest" must be one of the most-parodied cartoons of all time. The Wikipedia entry includes a good list of "Quest" spoofs, including Cartoon Network's show "The Venture Brothers," which is basically a week-to-week sendup of "Quest." But by far the best parody of "Jonny Quest," and one of the best parodies ever made anywhere, is the cartoon "Toby Danger," originally aired on "Freakazoid!"
"Toby Danger" wasn't actually created for "Freakazoid!," though. Tom Minton, a writer for "Animaniacs" who specialized in parodies of other genres and styles of cartoon (he'd done a famous episode of "The New Adventures of Mighty Mouse" incorporating vicious send-ups of other cartoon series), came up with the idea to do an elaborate parody of "Jonny Quest." The names would be changed, the character designs would be different, and even some of the characters would be entirely different (instead of Hadji, we got a teenage girl named Sandra Danger), but the inspiration would be obvious. The "Toby Danger" cartoon was written and storyboarded, but it wasn't put into production because no one could figure out where to put it: the limited-animation, non-cartoony style it required wouldn't have fit in with the very cartoony style of "Animaniacs."
Then "Freakazoid!" was suddenly revamped from a straightforward adventure-comedy into an out-and-out comedy, and with very little time to produce the new series, the producers were putting in just about anything they could to get 13 episodes ready in time. So "Toby Danger," with a script and storyboard ready to go, was put into production and aired as part of the second episode of "Freakazoid!" Some people liked it better than the rest of the show; me, I liked it all.
As storyboarded by Brian Chin and Butch Lukic (who are both caricatured in the cartoon, along with Minton), it's a great-looking cartoon (though a lot of retakes apparently had to be done because the overseas studio initially didn't make the animation limited enough), perfectly capturing the style and look of "Jonny Quest," and all the infamous things like the casual racism ("Heads up, you heathen monkeys!") and the scream everybody lets out when anything bad happens ("Aieee!"). But What makes "Toby Danger" a great parody is that it goes beyond just mimicking the style and look of the show and actually attacks the themes and messages of the original show. "Jonny Quest" was relentlessly optimistic about science and technology; the great scientist, Dr. Benton Quest, constantly saves the day with his inventions. In "Toby Danger," Dr. Vernon Danger is a deluded nut whose inventions cause more damage than they fix: one of his inventions is responsible for the carnage in the first place; he practically wipes out a city trying to save it; and he casually mentions that he adopted Sandra after his experiments wiped out her home town.
Minton wrote, and Chin and Lukic storyboarded, a second "Toby Danger" cartoon, but despite the acclaim of the original, it was never produced; "Freakazoid!" switched to full-length half-hour stories for its second season, so there was nowhere to put another "Danger" cartoon. It would be interesting to speculate on whether "Danger" could have succeeded as a full-length spinoff; I think it would have been better than "Venture Brothers," all told.