For the episode of the same name, go here.
Wacky Delly is an in-universe cartoon series created by Ralph Bighead and conceptualized by Rocko, Heffer and Filburt. It was produced at Bighead Studios in Hollo-Wood. Rocko and his friends worked on almost all of its episodes.
The plot revolves around 3 delly foods and their wacky adventures - Betty Bologna (voiced by Rocko), Sal Ami (voiced by Heffer) and Mr. Cheese (voiced by Filburt, and originally called Lester Roquefort).
Wacky Delly went under development after Ralph Bighead's other show the Fatheads ended after 893 episodes and the executives reminded him that he is required to create one more new show under the contract before he leaves. Ralph gave Rocko, Filburt and Heffer free rein in creating a new television show, hoping that their ineptitude will get Ralph out of his contract for good, after hearing Filburt declaring that Heffer's idea of a cartoon salami would get his contract cancelled.
Wacky Delly's production was troublesome, as Heffer and Filburt argued over the storylines of the show in a capricious manner, which completely annoyed Rocko to no end. At one point, Heffer considered removing the Cheese from the show, seeing as he wasn't really needed, much to Filburt's dismay. But, eventually, Rocko, Heffer and Filburt finished the production of the pilot episode for Wacky Delly.
Once the pilot was finished, Ralph then showed it to the executives, which turns out to be a huge, clunky, nonsensical mess. Despite how terribly-made the film is, the executives loved it, much to Ralph's shock.
Disappointed by the show's sudden popularity due to it squelching his prospects of being free to create his masterpiece, and trying to get out of his contract, Ralph frequently tried to sabotage the show, such attempts as having an episode being a continuous image of a jar of mayonnaise and over exposing an episode's film reel, but these attempts only ended up increasing the show's popularity. Even when Ralph got help from his father Ed and attempted to use the heat ray to destroy Bighead Studios by melting all of Antarctica and causing a giant flood. Unfortunately, at the time, Heffer used a crank to hoist Bighead Studios (which he thought was hoisting his car) over the impending flood caused by Ed's heat ray, much to Ralph's utter annoyance.
After yelling at Rocko, Heffer and Filburt, telling them how he hates the show and is trying to get out of the animation business to make "real art", Rocko told Ralph that he should be happy, as he is a much beloved animator and instead of hating Wacky Delly he should be embracing it, as his cartoons are his art. Ralph saw what Rocko said and decided to throw his full weight and support behind the show... only to have it promptly cancelled just a few seconds into the next episode.
In-universe, Wacky Delly went on to have a cult following, as some people fondly remembered the first season of Wacky Delly after 10 years of its cancellation, at least before "that new guy" ruined it.