Ass Pull: Played with in "Manic Mechanics". Rocko breaks his car, and all seems hopeless....until he notices a "Broken/Fixed" switch on the engine.
Big Lipped Alligator Moment: Tends to happen fairly regularly, but possibly the most notable instance is the scene with the naked fairies and the shaved voyeur gopher in "A Sucker for the Suck-O-Matic".
Heffer being abducted by aliens who look like him in the episode Cruisin. Even though they went into the Bermuda Triangle and went through a time warp, this makes no sense in relation to the rest of the episode.
Also, the following exchange in "Bye Bye Birdie":
Heffer: Hey Rock, do you want to move to France? (not taking eyes off TV)
Rocko: Not really. No. (eyes also glued mindlessly to TV)
Heffer: Yeah, me neither. (and they just continue watching TV)
Though they don't move there, Rocko and Heffer do go and visit France in a later episode.
Cargo Ship: Canon: Spunky's forbidden romance with a mop.
The Psychiatrist was shown later to be wining and dining said mop.
And how does Spunky get over it? He falls in love with a fire hydrant!
Cult Classic: The show was never quite as popular as The Ren & Stimpy Show or SpongeBob at the time; the best it could manage was this. The cult fanbase, though, was enough so that the show was on MTV for a brief while.
Growing the Beard: While season 1 was certainly funny, it was much more low-key, as it focused more on it's Vanilla Protagonist Rocko. The show evolving into an ensemble comedy not only brought the much funnier side characters center stage, but provided some of the funniest jokes, eventually leading to the excellent third season, which even Joe Murray agrees was the one where the show was really firing on all cylinders.
Harsher in Hindsight: In "A Sucker For the Suck-o-Matic", Heffer is channel surfing and we hear a reporter say this: "The official motorcade is just coming around the corner now, and... oh my God! There's a burst of gunfire!" This is really not funny considering the mass shootings of the '10s.
On April Fools' Day 2013, The 90s Are All That announced they'd air a lost episode of the series, which turned out to be a picture of mayonnaise. 3 years later, an hour-long special was announced. Looks like Rocko is back for real.
During production on season 2, Joe Murray's wife tragically killed herself. Murray later revealed that she was the one who made him more environmentally conscious and encouraged him to recycle, meaning that she was the inspiration for the much-loved Musical Episode "Zanzibar" a year later.
"Heff in a Handbasket," The episode where Heffer sold his soul to be on a game show, was once pulled due to its blasphemous content. Eventually, the episode did air again on June 6th, 2006 (6/6/06) on Nicktoons TV. Guess the Nickelodeon censors didn't see why would this be inappropriate.
In one episode, Filburt has a tube of a toothpaste-like substance called "Spirit Away". It's also funny if you're a Touhou fan, as Ran has a spell card called "Yukari's Spiriting Away".
One episode features Heffer choking to death, and the Grim Reaper comes and mockingly tells him he was killed by his own gluttony. Heffer cries, "I'M A GLUTEN!!!" This was a good long while before the anti-gluten diet craze.
Narm Charm: This is the whole reason "Zanzibar" is a musical. While Joe Murray is a self-proclaimed environmentalist, he was reluctant to do an episode about the environment out of fear that it would be too sentimental or pushy. The other writers convinced him that a Musical Episode would allow them to be tongue in cheek without harming their message, with Murray's only condition being that Rocko wouldn't sing, lest it be too silly.
Padding: The original "Trash-O-Maddnes" indie short, which Murray animated solo, is only five minutes long, so the broadcast version added new scenes from the overseas studio, and its quite obvious which is which: the Murray animation is looser and has rougher audio, while the overseas animation is more on-model, has cleaner audio and doesn't much affect the plot.
So Cool, It's Awesome: Even as a "short runner" (or considered short in comparison to some of Nickelodeon's otheranimatedshows), this show remains one of the '90s most universally well-liked cartoons. The fact that it never experienced true Seasonal Rotnote Save the slightly weaker fourth season, when the writers were beginning to lose steam and Joe Murray was busy coping with his wife's suicide., had mostly likable and sympathetic characters and its clever writing/humor which only becomes funnier with age also helps.
Squick: The end of the episode "The Fatlands", not only does Dr. Hutchinson give Rocko all of the fat that she sucked out of Spunky... Heffer ends up eating that fat.
They Changed It, Now It Sucks: Though it doesn't affect the show as a whole, most people agree that the original theme song from season 1 was better than the B-52's version.
Vanilla Protagonist: Rocko himself. He is the Only Sane Man of the in-universe in contrast to the much quirkier and inane side characters. Not coincidentally, when said side characters got more attention, the show became much more popular.
What Do You Mean, It's for Kids?: Aside from the hidden dirty jokes and crude humor (some of which has been cut from reruns), the show's deals with themes you'd find on adult cartoons like The Simpsons (back when it was the sitcom to watch to laugh at jokes about how hard modern life can be), such as infidelity, immigration, racism (shown as "animalism" on the show), death, and cults.