In "Future Schlock", Heffer and Rocko don't seem to have aged much or to be otherwise worse for the wear after seventeen years in space. If they traveled at relativistic speeds, more time would have passed on Earth than would have on the spacecraft.
Ed Bighead, a cane toad, has an adversarial relationship with Rocko, who's from Australia.
In "Feisty Geist", Mortimer Khan takes over Filbert's body. Just as Rocko and Heffer prepare to squirt him with Spirit Away (TM) cream, he is already spirit free. They find him just washing his hands by the sink after using the bathroom. Mortimer surprise attacks Heffer as a toilet soon after. Mortimer didn't willingly leave Filbert's body, but passed out of him while he was on the can.
Dr. Hutchison lays an egg, even though she's a cat. This makes no sense initially, until one recalls that her father is a turtle. So Dr. Hutchison lays eggs because she's half cat, half turtle.
Dr. Hutchison at first glance may seem like an odd couple for Filburt, but they share quite a few things in common that some may take for granted. For one thing, both keep changing jobs and both have aform of handicap. Their lifestyles even complement each other, with the constantly ill Filburt (who keeps breaking out into hives) and Hutchison being a Doctor and Hutchison's purple clothing is even complementary to Filburt's green shell. And, last but not least, Hutchison's parents are also a turtle and a cat, which may make her attraction to Filburt inherited.
In "Canned", Rocko gets fired and we see a montage of other jobs he's taken. At one point, we see him talking on a phone saying "Oh Baby, Oh Baby, Oh Baby" (See the Radar page for more details). He gets Mrs. Bighead, and they both hang up upon recognizing each other. A few episodes later, in "Leapfrogs", we see the Bigheads' marriage is on the rocks because she feels unloved. Understand why she called that hotline now?
In "Heff in the Handbasket," Peaches is said to have not delivered a single mortal to Heck in over 600 years prior to Heffer. Yet, Heffer's grandmother is later shown as a resident of Heck, implying that she is over 600 years old.
Unless she was brought down there by one of Peaches' colleagues or his boss.
Keep in mind anytime Heffer goes down there, he goes back to Earth. It's also possible everyone else has gone to Heaven, meaning they live in aCrapsack World.
Mrs. Bighead has a raspy voice because she smokes, or used to.
Joe Murray kind of confirmed this; Mrs. Bighead was based on an older lady who lived in his childhood neighborhood, who also had a rather raspy voice because she was a heavy smoker, and who would often try and hit on the younger men in the neighborhood as well (like how Mrs. Bighead tried coming on to Rocko to make Ed jealous).
A bit of fridge brilliance regarding that guy who was racist against sea mammals; he claimed that he thinks all the sea mammals should be boarded onto a boat, sent out to sea and sunk halfway. This doesn't sound like a very effective method of killing sea mammals, but then you realize that he wasn't talking about killing them—that was the anti-sea mammal equivalent of "Go back to your country!"
When the gang meets the person formally known as Ralph in Static Cling, she gives Rocko an off-model ice cream pop that Rocko assumes is Mr. Fathead, but he is corrected that it's meant to be Mrs. Fathead. This makes for some subtle Five-Second Foreshadowing of Rachel's transition.
Two words that would make that scene even more horrifying to think about: Chick Culling.
It's been implied, more than a few times, that Mr. Bighead is willing to kill Rocko and his friends just to get rid of them.
The Chameleon Brothers make and sell videos edited from their clients' raw footage without their permission. Rocko walks in just in time to see footage of him naked displayed in front of an audience, and the end of said episode has the gang accidentally obtain one of the Bigheads' private videos. How many customers' trust have the Chameleon Brothers violated this way, and how many videos of their patrons' intimate moments have they profited off of? Better question: Aren't they afraid they'll be sued or run out of town?
Before putting Rocko in charge of Kind-of-A-Lot-O-Comics, Mr. Smitty rather tersely warns Rocko not to touch the Green Button on his chair. When Rocko gives into temptation and presses it, he turns into a Bad Boss himself. Did that mean Mr. Smitty was once a Nice Guy, only to turn into the man he is today from pressing the green button? Was that tiny glimmer of goodness still in him trying to warn Rocko not to share his fate?
Who CREATED that button in the first place?! Is there some sicko out there who decided that the world needed a button that turned someone into a Bad Boss whenever it was pressed?
Part of the running gag of the show is someone mistaking Heffer for a cow, only for Heffer (or his adopted wolf father if he's present) to correct them, claiming he is a steer. However, Heffer should have referred to himself as a bull, since steers are male bovines that have been castrated before reaching sexual maturity. Now while it's likely that Heffer is just not knowledgeable about his own species history and anatomy (among other things), the fact that his father does this as well raises a lot of unfortunate questions when one looks at Heffer's backstory.
Heffer was originally going to be his adoptive family's dinner, thus they fattened him up and even placed plotted lines on his butt to show how they were going to divide him (which Heffer thought was a birthmark).
Yet over time they grew to love him and raised him as one of their own.
But maybe the Wolfe family didn't just fatten him up? Maybe they did more than that? When a bull is castrated as a calf, their bodies begin developing differently from uncastrated bulls. Not only does the process make steers more docile due to reduction in testosterone production, it also changes their muscular development that makes them physically similar to female cattle sans the udders. In addition, most male cattle that undergo this procedure are primarily used for meat production. Perhaps the reason why most of the people on the show call Heffer a cow isn't just because they're misinformed, but because Heffer is an in-universe version of Viewer Gender Confusion. It also raises the question on whether or not the Wolfe family actually castrated Heffer when he was only a calf to make him less aggressive and easier to handle for butchering. It certainly explains why he became the overgrown and easily dupable slob he is today.
The gender confusion is compounded on by Heffer's name. A heifer is a young female cow, so Heffer has what is essentially the animal equivalent of a female name.
On the other hand, several episodes clearly show Heffer being in love, and definitely capable of arousal, as one milk machine mishap showed.
You can definitely fall in love after being castrated. It's also possible to become aroused and even achieve orgasm — it just takes longer.
As mentioned above, Heffer is a steer (which is a castrated male bovine). If he's castrated, then how was he able to feel aroused by the milking machine in "The Good, The Bad, and the Wallaby"?
Also, how was he able to provide DNA to Filburt and Dr. Hutchison's egg?
Well, I can't answer the milk-machine question, but the egg thing was implied to be because he farted on it.
Castrated males can still feel pleasure and even orgasm. It just takes some extra time/effort.
It's shown that an accident at Rocko's store caused the pink rabbit seen in some episodes (the one with his tongue sticking out) apparent brain damage, thus explaining why he appears like that. However, it's shown in an earlier episode (in a flashback no less) that he's had brain damage back then, too. Did he get cured only to fall victim to another brain injury?
Joe Murray has stated that the continuity errors in the flashbacks (Rocko knowing Heffer and Filburt as kids, them meeting as adults, Rocko coming to America as an adult, etc.) were intentional because it was a parody of how people remember things differently and false memories. Other than a few nods here and there, this show wasn't the biggest on continuity. Most Nicktoons at that time, in fact, weren't; they had to really fight for Paula and Filbert's wedding, which was the first hint of any semblance of continuity in any of Nickelodeon's shows.