Invader ZIM was an Animated Series by Jhonen Vasquez, which premiered in 2001 on Nickelodeon. Reruns are still being shown on the Nicktoons channel as of this writing.Set Twenty Minutes into the Future, this dark, Cyberpunkish show starred ZIM, an Irken Invader sent by the Almighty Tallest to take over Earth (read: shipped off here because he screwed up on his last invasion attempt; they just want to get rid of him, but ZIM doesn't know this).note In fact, the Irkens aren't even sure there's a planet here; they just want ZIM gone that badly. He is ineptly aided in this "mission" by a defective robot assistant named GIR.This "alien invasion" attracts elementary school student Dib, a self-styled paranormal investigator just itching to expose something strange and weird. And ZIM seems just the alien to expose...Early episodes followed a rigid formula— ZIM would attempt to get rid of Dib and conquer the world, while Dib would attempt to expose ZIM, only for both to discover that Failure Is the Only Option— but later episodes used a Snapback to do all sorts of bizarre things unrelated to the plot. Ultimately the efforts of Vasquez and head writer Frank Conniff developed into a much more idiosyncratic, hammy, and satirical style.The dark humor and interesting storylines attracted loads of people outside the targeted age range. Part of the reason for this is the show's distinctive art and writing style. The art style is a variation of Jhonen Vasquez's previous work, simplified for animation. The show's art style was very elaborate regardless, and colorist Rikki Simons jokes that they went into "fourth-ary" colors (most cartoons try to stick to primaries), leading to a hefty price tag of $500,000 per episode.note This was actually the standard Nick Toon budget, but none of the others struggled with it the way Zim did.Unfortunately, the show was gone quickly. While quite popular, especially outside of Nickelodeon's typical demographic, its ratings did not have far to slip before Nickelodeon deemed the show's hefty price tag not worth further expenditure. This alone would have provoked mass outcry, but Nickelodeon also declined to sell the show's copyright (and there were other networks interested in purchasing it), to the dismay of creators and fans alike. The Internet Backdraft was considerable, but sadly, largely unsuccessful, with one exception—Media Blasters getting the rights to sell DVDs of the show. (The Media Blasters DVDs have since gone out of print, and Amazon.com has released their own Vanilla Edition collections of the show in an attempt to fill the void. Nickelodeon has also released a "best of" disc, Operation Doom. All of which were only released in North America.)Not all was lost, though. Its was the sudden and unexpected unemployment that convinced the show's art director, Bryan Konietzko, to develop a show with his old college friend. As such, from Zim's ashes emerged Nickelodeon's powerhouse series Avatar: The Last Airbender.Despite its short run, the show had and still has an über-huge fanbase, some of whom even now cling to the hopes of a revival. While logic would tell you that the odds are against it, even as late as 2010 Nickelodeon actually has considered the prospect, and by his own account Jhonen Vasquez would be willing to return should such a thing happen (which it most likely will not, but it's nice to know). In the meantime, you'll find yourself with plenty of company should you go looking for fellow fans, but this can be a bit of a double-edged sword given the nature of rumor on the internet, leading to the spread of a lot of well-intentioned but often grossly inaccurate information, especially regarding the circumstances surrounding the show's untimely cancellation (in a semi-recent blog post, the creator himself has noted that even IMDB and Wikipedia contain errors). Be wary of what you read.With that said, sometimes even the craziest rumors do wind up with a grain of truth to them. In September of 2010, Jhonen Vasquez disclosed in a blog post that Nickelodeon had been seriously considering a revival, as ZIM's ratings on Nicktoons were scoring second only to Avatar: The Last Airbender.
Adults Are Useless: And how. So are most of the other children, for that matter. And a lot of the aliens. Really pretty much every one and every thing in this show is useless. The only person that comes the most to non-useless is Dib, yet at times even he is useless.
The Irkens must have some interesting naming conventions, as the individuals who are identified are ZIM, Tak, Skoodge, Spleen, Tenn and... Bob.
Even human children have an odd mixture of names. Nick, Kevin and Mary coexist with the likes of Dib, Gaz and Moofy.
The common pathron appears to be monosyllabics, as every three-letter name is one (Dib, Tak, ZIM, GIR, Gaz, and even concepts as Irk and PAK) and most of the other names are this too (Spleen, Keef, Tenn).
ZIM's computer, after admitting it doesn't have enough information about the FBI, just makes up a bunch of crap. Then again, it only did so because ZIM ordered it to make some "educated guesses" when it didn't have any info to work with.
After being modified by a fed-up ZIM, GIR loses his Cloud Cuckoolander tendencies, and becomes very dedicated to "the mission". Unfortunately, he judges ZIM himself detrimental to the potential success of "the mission"...so he decides to eliminate him.
GIR himself. He randomly shifts between a rather scary, red-eyed "duty mode", and his usual, hilariously stupid (and blue) persona. This may have something to do with being cobbled together from junk parts.
Agent Darkbootie, a high-ranking member of the Swollen Eyeball, apparently has a day job as a janitor at NASA.
Sizz-lor is a very high ranking Irken ... Fry Cook.
All There in the Manual: A lot of minor aspects of the setting and background for ZIM and the Irken race as a whole are only known thanks to Word of God from Jhonen Vasquez. Much of this backstory and extra info was going to be shown later on in the series but y'know...
Always Chaotic Evil: It isn't explicitly stated or anything, but one could infer this about the Irkens.
Art Evolution: Subtly. Most prominent when ZIM and the other Irkens are suddenly drawn with two fingers and a thumb, to set them apart from humans.
Artificial Human: In the DVD writer's interview Eric Trueheart said that had the show gone on for several years, Dib would have discovered (while on a quest to discover why his life was so horrible) he was one, created by Membrane.
All over the place in "Planet Jackers". Parodying the Twin Cities bit from Fargo, one of the pilots points out a binary star system, implying it's a rare sight. However the truth is that most stars in the galaxy, or at least the most visible ones, are part of a binary system.
Audio Adaptation: Seven of the unfinished episodes already had their voice tracks recorded, so they were released on the Special Features DVD.
Author Appeal: Well, more like Creator Appeal, as Jhonen has a thing for saying the words "Doom" and "Dooky", makes references to piggies, and has a good number of morbidly obese jokes in some episodes.
In "Career Day," ZIM is told his ideal career is as a fast food slave, and the episode, like most others, suffers from Negative Continuity and so the viewer thinks nothing much of it. Fast forward to "The Frycook What Came From All That Space," and we learn that an Irken Control Brain reprogrammed ZIM's PAK to register him within the Irken Empire as a fast food slave on Foodcourtia.
The joke started even earlier, in the first episode:
Tallest Purple: Weren't you banished to Foodcourtia? Shouldn't you be... frying something?
Super Toast, from the first episode to "Future Dib".
"All while gathering crucial information, assessing the planet's weaknesses, making it vulnerable to our big... space ship... gang!" "Score one for the human race! Score nothing for the ZIM... thingy... race." "By the way, it's not called parent teacher night, it's called ZIM doom parent... ZIM doom ZIMMY... doom... night."
This trope is taken to an absurd, horrific degree, to the point that it deters people from eating fast food and watching the show with a clear conscience. Pretty much every fast-food chain is portrayed as a disgusting, horrible place to eat or work, with the likes of Crazy Taco, Mac Meaties, Bloaty's Pizza Hog, and Chicky Licky.
Taken to it's logical extreme with Foodcourtia, an entire planet dedicated to fast food. Apparently because of Zim's banishment there, inflicting this on Zim is now Sizz-lor's job description. And he likes it.
"Yes, yes, so you blame me for your horrible life, blah, blah, big deal!"
Butterfly of Doom: When ZIM starts sniping at Dib via a temporal displacement device, Dib starts accumulating more and more debilitating injuries, and is eventually driven to the point of death... After which he is revived and equipped with a bionic exoskeleton by Professor Membrane. All further attempts on Dib's past life result in upgrades to the exoskeleton.
Dib, to the point where when he and ZIM are piloting Mercury and Mars respectively in "Battle of the Planets", Dib is piloting the Butt of Mercury, and gets there by a spaceship that was once used to shoot monkeys into space.
ZIM fares slightly better compared to Dib, but he's been kicked around several times as well. Be it due to his various horrible injuries, frequent failures, or being despised by his own species due to his own incompetence and violent nature.
The Cake Is a Lie: In "Door to Door", ZIM and Dib's class is selling Poop candy bars for a fundraiser, promised that the student who sells the most candy bars will win a mystery prize. ZIM goes to ridiculous lengths to get it, eventually selling 1.2 million candy bars, only to find out that there was no mystery prize, it was just made up to get the kids to sell more candy bars. But hey, they gave him a can of tuna as consolation.
Chekhov's Gun: When we first see the nurse in "Dark Harvest", she's playing with a mooing can. At the end of the episode, ZIM uses it to replace one of Dib's organs (we are not shown which one).
Character Overlap: In the Johnny the Homicidal Maniac spinoff, titular character Squee is in Ms. Bitters's class (although she is never given a name here), and nearly gets abducted by the two idiotic aliens from the ZIM episode "Abducted" a total of three times. The aliens first appeared in the original JTHM comics.
Compulsory School Age: ZIM's older than any human alive, and in "NanoZIM" he taunts Dib that he's been flying ships since before Dib was born, yet he attends what appears to be an elementary school — and with his height, he fits in, although he really shouldn't. He opted to do so, believing it to be the best way to retrieve information about the species he intends to conquer.
Conspicuous CG: It doesn't blend in as well as, say, Futurama, but it still looks pretty good. The creators lampshade it in the DVD commentary for "A Room With a Moose", claiming that they spend the whole season's CG budget on the 3D walnuts.
Probably the best example of this is the way it's possible to trace the fate of planet Vort — it's singled out for conquest in "The Nightmare Begins," seen briefly in "Walk for Your Lives" as the Tallest check up on the Invaders, is in the very next episode ("MegaDoomer") mentioned to have been conquered, in "Backseat Drivers" we learn it was turned into a prison, and in "Frycook" we hear about the faulty security systems that were initially put into place, presumably explaining how the Resisty's Vortian captain (Lard Nar) is out and about.
In the unproduced script "Day of Da Spookies" ZIM taunts Dib with knowing nothing about aliens, perhaps a nod back to "Room with a Moose" when Dib did not even know what ZIM's home planet was called. However Dib gives an update on what he's learned since, touching on other episodes in the process: ZIM is from a race of planet-stealing aliens called Irkens ("The Nightmare Begins"), their brains are contained in their backpacks ("Ten Minutes to Doom"), their eyes are synthetic implants (somewhat implied by "Planet Jackers"). The display thoroughly spooks ZIM.
Creator Cameo: Various writers and animators were drawn into recurring background characters (including Frank Conniff, a.k.a. TV's Frank). Series creator Jhonen Vasquez provided the voices of both ZIM's computer and Minimoose.
Credits Gag: Done in the episode FBI Warning, with the titular FBI warning in the beginning of Intestines of War. Apparently, most FBI warnings are made by people threatened by smelly piggies.
"The Federal Bureau of Investigation investigates allegations of criminal copyright infringement. They will hunt you down like the dirty monkey you are and force you to wear a moose skin and ride a greased piggy while singing folk tunes. They’re forcing me to ride the piggy as I write this. The piggy is smelly!"
In "Walk of Doom", ZIM walks into the tallest building to get to the top to get his bearings of the city. As it turns out, that building is a bank that was just robbed, and his human disguise looks just like the bank robber. Cue Chase Scene.
Dick Dastardly Stops to Cheat: ZIM'd be a lot more effective if he could just learn when to quit. In "Bad, Bad Rubber Piggy" Dib had lost just about all of his ability to represent a threat to ZIM, but his continued attempts to KILL him after he'd already been crippled backfired rather spectacularly.
The episode "Dib's Wonderful Life of Doom" is practically made of this trope. Dib throws a muffin at ZIM during lunchtime at Skool one day. What does ZIM do to retaliate? He constructs a brilliant Lotus-Eater Machine for Dib based on everything the boy wants to do in life, and in Dib's twilight years, while being interviewed on a TV show celebrating his accomplishments, the TV host asks Dib if he'd been the one who threw the muffin at ZIM all those years ago. Dib answers yes, and suddenly, ZIM's face appears on the faces of everyone in the audience. Dib wakes up, in the real world, connected to a machine in ZIM's lab. With this unpleasant little fact known, ZIM coldly tells Dib to get out. Crushed, Dib begins walking away, only to have a gigantic gun aimed at his face. What fires out of the gun? A muffin.
Zim: If I can bring the time field around the explosion back up to regular speed, it'll fix everything.
GIR: No it wooooon't!
Zim: The explosion will blow up like normal and be gone foreveeeer!
GIR: But won't it just explode? JUSTLIKETHIS, KABLAM!
Also in "Plague of Babies":
ZIM: GIR! We've been seen out of our disguises! By a human! GIR: But Dib's seen us. He knows where we live!
In "Walk of Doom", when ZIM and GIR get horribly lost in the big city:
GIR: Why don't we just ask the information humans for help?
Dib's continued crusade against ZIM, really. Yes, it's true that ZIM is too stupid to deliberately conquer the world, but he's also crazy enough to accidentally destroy it. Keeping ZIM focused on fighting Dib really is keeping the world safe... just not quite in the manner either of them thinks.
Dysfunction Junction: ZIM is an egomaniac and strongly implied to be legally insane, GIR is a crazed Cloud Cuckoolander, Dib is a Butt Monkey who desires affection and validation, Gaz is freaking scary, Professor Membrane is a Mad Scientist and neglectful father with a burning hatred for Santa Claus, and Skoodge is an oblivious Butt Monkey. And that's just the main cast! The universes status as this would have been delved into more had the show gone on longer.
Likewise Bill, a paranormal investigator who believes that cereal mascots are real, nevertheless insists that dinosaurs are a fraud.
Everything's Better with Monkeys: The Angry Monkey Show, Suckmonkey, "babbling like a maniac-monkey" "screaming like a howler monkey"...the list goes on. It should be noted that Jhonen Vasquez's original works often refer to monkeys a lot and this show is no exception.
Two specific incidents that make little sense, however: In the first episode, the writing staff changed radioactive rubber ants to rubber pants simply due to Rule of Funny. In the words of Jhonen, "Suddenly we had a fight on our hands!" And in a later episode, they had to fight to keep a line in where a kid told his mom to have fun at work because Nickelodeon thought it was inappropriate to have that line. Why? Because it's about one in the morning, leading some to conclude that the kid's mom was a prostitute.
Due the show's proximity to 9/11, some elements (firefighters watching the slow explosion from their fire truck in Walk For Your Lives, vision of destroyed New York in Door to Door) were deemed too offensive to air. The explosion was turned green instead of orange, the firefighter gag was removed and a new "horrible future" vision was produced for Door to Door. Jhonen Vasquez said he preferred the new vision to the old one, as it was more violent.
A moment in "GIR goes Crazy And Stuff" is particularly famous for subverting this and what follows. An image of GIR dripping with blood was declined by the network and did not blatantly appear in the episode. The "Bloody GIR" became an Easter Egg in the series, hidden faintly into frames.
There's also a brief moment in "Planet Jackers" where, after crashing his cruiser, ZIM's eye pops out of its socket and into his hand for a couple of seconds. He quickly replaces it, but.
While it's only shown in silhouette, "Bestest Friends" ends with Keef's eyes being ripped out by a machine and replaced with a pair of robotic ones that also filter his vision.
It gets better! It's implied that while being attacked by a squirrel on the roof of the building next to ZIM's house, Keef fell off and the impact CAUSED HIS NEW EYES TO EXPLODE.
Failure Is the Only Option: ZIM will never conquer the Earth and Dib will never reveal ZIM as an alien. More often than not, one's failure causes the other. Gaz herself knows this and as such she never really gets involved in their rivalry willingly.
Dib: Don't you care that ZIM is trying to destroy all mankind? Huh? Gaz: But he's so bad at it.
Fate Worse Than Death: Not in the show itself, but in the online game Dib's Nanochase, if the player loses, ZIM succeeds in screwing up Dib's brain, leaving him a retarded vegetable.
Keef's stalker-ish aspects were highly amplified in "the Return of Keef" compared to his original appearance.
Dib got comparatively more crazy and "ZIM-like" as the series progressed.
Follow the Leader: After Invader ZIM hit cult status and became immensely popular with the preteen demographic, many other animated TV shows started turning towards dark and random humor. Grim Adventures of Billy and Mandy, Courage the Cowardly Dog, The Misadventures of Flapjack, Adventure Time, and Making Fiends are a few examples.
Humanoid Aliens: Almost all of them. The Meekrob, the Slaughtering Rat People, Shloonktapooxys of the Resisty — and possibly the Plookesians — are some of the only exceptions.
Well, a lot of the background aliens look different, though a loose humanoid form does seem to be standard for "important" races.
Human Outside, Alien Inside: Despite the fact that ZIM appears to be able to pass for human with only a minimal disguise, his inner workings appear to be quite different. "Ow, my squeedlyspooch!"
ZIM: "Don't come any closer! Don't try anything on me or I'll...I'll...I'll lay eggs in your stomach! I mean it!"
Although that one may or may not have any basis in reality as he was primarily trying to scare off his "worshipers".
Humans Are Morons: Every human is an idiot, except for Gaz, Dib, Agent Darkbooty and Professor Membrane. Although it should be noted that the whole universe is portrayed as stupid much of the time, so they're really not any worse off.
Humiliation Conga: Everything ZIM had set up for the humans in "Backseat Drivers from Beyond The Stars" blows up SPECTACULARLY.
Hypocritical Humor: "Attack of the Saucer Morons" opens with ZIM flying around in the Voot Cruiser making police cars crash to test Earth's defenses. He concludes that Earth vehicles are "PATHETIC!!" ZIM's ship then collides with a bee and explodes.
Insane Troll Logic: Oh there is a lot for this show. But one noticeable one is when the School Psychiatrist stopped believing in aliens because his foot got trapped in an escalator and aliens didn't come to save him.
The most humorous example of this is the mutated hamster episode, which ended with a still frame saying that nobody died. If you listen to the commentary of that episode Jhonen and the other cast members off-handedly mention "Oh, he's/she's dead" and completely ignore the still frame.
No Ending: As mentioned under negative continuity, a lot of episodes just end with no resolution to the conflict of the episode.
Also, Screamy, a Skool student from the unfinished episode "10 Minutes to Doom."
Noodle Implements: The final tier of ZIM's test to see who is most fit to be his friend involves a toy taxi and a stuffed beaver. Whatever happened, it took half an hour and left the other participants other than Keef covered in third degree burns and barely conscious.
The third degree burns were from ZIM's second test of electrical conductivity.
One-Man Army: Apparently skilled-enough and well-equipped Irken Invaders are capable of conquering the planet by themselves, though it seems it's mostly a case of leaving it up to their technology to do it once they enter the planet.
Hell, a single functional SIR unit seemed pretty capable of conquering the planet, as shown during the episode where GIR gets (temporarily) repaired, and with Tak's functioning SIR unit.
One-Product Planet: Foodcourtia, the food court planet, Callnowia, the mail-order planet with Conveyor Belt Planet for shipping, Blorch, which is now the parking structure planet... the Irken love doing this.
The Only One Allowed to Defeat You: Drives the plot of both "Planet Jackers" and "Tak, the Hideous New Girl," as ZIM won't tolerate an attempted takeover/destruction of Earth from anyone else.
ZIM: The Earth is mine to devastate! And I already promised the moon to GIR.
Only One Name: Dib and Gaz do not seem to have a last name (ZIM's holographic Meekrob refer to Dib as "Dib... whatever-your-last-name-is"). A Nick.com e-card for the show claimed that Membrane's first name was Professor, but Jhonen (and the original flash version of official website) says that, in fact, Membrane is the professor's first name and his last name is a mystery like so many other things about him.
Dib replies to "Dib... Whatever-Your-Last-Name-Is" with "that's right," which could be taken as confirmation of its correctness, unless he was just confirming his first name, or agreeing that it wasn't important and indicating that the speaker should just continue with their main point.
Though this hasn't stopped fans from referring to Dib as "Dib Membrane," however, who seem to love using that as his last name. On occasion Jhonen himself has even referred to him (possibly mockingly) as "Dib Membrane" on his blog.
ZIM's disguise consists of a wig and two contact lenses.
GIR's dog disguise is green with a visible zipper.
ZIM's robot "parents" only bear a superficial resemblance to actual human beings, yet fool a roomful of people at ZIM's parent-teacher conference. Even when "dad's" arm blows off in a shower of sparks, ZIM is able to handwave it.
"My Dad lost his arm in, uh, the War." "That was my squeezin' arm! They took my squeezin' arm! Why my squeezin' arm?"
Then there were the literal paper-thin disguises of the aliens in the episode "Abducted". They were basically thin smocks with an image of a human body, and what appears to be papier-mâché masks. (This is made even funnier by the fact that they're supposed to be husband and wife, and they got the nametags mixed up.)
In "Planet Jackers" when ZIM is looking through his telescope at the other Invaders, the only one we see is in disguise basically has a rock strapped to his head, making ZIM's costume look brilliantly thorough in comparison. It is apparently sufficient to fool the natives, however, who are seen fanning him.
Tak, at least, had a reasonable disguise though.
Then there is ZIM's secondary disguise from The Girl Who Cried Gnome and The Mose Horrible X-Mas Ever Which has his undisguised face peeking out through the mouth of the costume. Hilariously, at the end of Girl who Cried Gnome an artist's rendition of the "hero who saved the little girl" shows that they saw through the disguise, but still thought he was human as the depiction shows a normal human face peeking out of the costume's mouth.
Parody Sue: In "Dib's Wonderful Life Of Doom," when Dib gets superpowers (or seems to).
Pet the Dog: ZIM treats GIR noticeably better than everyone else and actually expresses concern for his safety multiple times. He gets a few other moments where he treats people surprisingly well, but for every Pet The Dog moment ZIM gets, he gets three Kick the Dog moments in return. This prevents the audience from forgetting that ZIM is a bad guy.
Pick on Someone Your Own Size: Interesting subversion here, as ZIM and Dib are the same size, and ZIM is from a culture that directly equates worth with height. The result is a rivalry that by all logic should be completely one-sided, as an alien older than any human on Earth, equipped with technology they could only begin to understand, finds an arch-nemesis in a grade-schooler.
Planet of Hats: ...sort of. The planets that have been conquered are retrofitted to suit the Irkens' needs: Foodcourtia, the food court planet; the convention center planet; the shipping center planet; Hobo 13, the military training-planet; and so on...
Played straight straighter with some mentioned planets and dimensions such as: Exploding head planets, broken glass planets, a dimension of pure itching (you can't tell from the photo, but that stuff's really itchy), and a dimension of pure... organic material.
Dib: The only way back home is through my head! Anything happens to me and you're stuck here forever! ZIM:NOOOOOOOO! CURSE YOU!...Wait. I can still do stuff to your legs, right? Dib: I guess, but — wait! No! ZIM:NOOOOOOOO! CURSE YOU!
Reality Ensues: "FBI Warning Of Doom" has the villain of the week try to kill ZIM with zombies. Except that the zombies just sort of wander about uselessly and run into things. As it turns out, a mindless corpse that just sort of shambles towards people trying to bite them isn't exactly a huge threat.
Red Oni, Blue Oni: Used most prominently in "Rise of the Zitboy." ZIM is red and Dib is blue.
Reed Richards Is Useless: Professor Membrane parodies this. He's quite capable of creating such things as a Perpetual Energy Machine but will also on a whim decide that the populace is undeserving.
He also averts it. The official website stated that he routinely creates miracle cures for all the ills of the world (according to Gaz, Taster of Pork, he considers it incredibly horrifying that he still hasn't found a cure for "pigmouth" after one day of trying). With apparently no effect, since the world still sucks.
Regional Bonus: In "Game Slave 2", Iggins mentions that he already had the Japanese version but wanted the American version as it had a new level.
Ridiculously Human Robot: GIR. He is undisputably the most insane character in the entire series. "He" eats with Extreme Omnivore tendencies, (in Halloween Special of Spooky DOOM he attacked every trick-or-treater in the vicinity of ZIM's house, apparently getting a sugar rush, then eating all their candy and becoming even fatter than the guy in the costume at Bloaty's Pizza Hog.) drinks, sleeps, has a sense of smell (in one episode, for no discernible reason, he held a smelly dog in front of ZIM and yelled "look what I found! He smells reeeeeealll bad!), cries, parties down and basically acts like a human child. "He" is also assembled from random bits of garbage, and is dangerously (and often explosively) defective.
Dib's (supposedly) big head, Membrane considering Dib insane, and spinal injuries.
The mentioning of moose.
During a crowd scene with people cheering, there's usually gonna be someone yelling "[Thing we're cheering about] rocks!"
ZIM losing interest in whatever he's doing at the moment.
Dib: You're going to use it to walk right past security at the generator, aren't you?! (ZIM takes a few seconds to finish drinking his soda) ZIM: Ah... What? Oh...(turns on the Large Ham) OH YES!
While a lot is made about how terrible ZIM's disguise is, if you pay attention you'll notice that all of the invaders we ever see in disguise are pretty terrible. Apparently tying rocks to your limbs or a prosthetic nose is all you need to get by as a covert agent. Tak alone seems to be the only invader to avert this.
"Hi, I'm Eric Trueheart, and I had nothing to do with this episode!" (This one was repeated to the point where, when an episode he did write gets commentary, everyone else involved absolutely refuses to believe he wrote it. Richard Horvitz thinks Trueheart just transcribed it or something.)
Sanity Ball: GIR seems... different... in the episode Walk For Your Lives. He's a lot more focused than usual, and is quick to point out the obvious flaws in ZIM's plans.
Save the Villain: Dib agonizes over whether or not to save ZIM in "Hamstergeddon" — on the one hand, Zim's the only one who can stop Ultra Peepi, but on the other ZIM will return to his attempts at world-demolition if Dib saves him. In a funny subversion, ZIM recovers just fine on his own while Dib is agonizing over the decision.
Shadow Discretion Shot: A running gag in the series. Most notably with Keef getting his eyes ripped out, or in "ZIM Eats Waffles" when he grabs something (slightly resembling a plunger) and blasts away the demon squid.
Shouldn't We Be in School Right Now?: Fairly well averted, as very little seems to get past Mrs. Bitters. ZIM or Dib (mostly ZIM) will mysteriously go absent occasionally, usually to plot revenge, but all battles for world domination must take place after school, or under the guise of a bathroom break.
ZIM gets spiked in the face with one of these whenever Dib threatens to blow his cover, pulling off such stunts as nanoscale laser brain surgery, zit-based hypnosis and bulk organ theft.
Dib also catches hold from time to time, repairing alien spacecraft and hacking into supercomputers.
Snapback: Quite a few. Some could plausibly have an off-screen explanation, like "Planet Jackers," while others apparently stand in total defiance of canon ("Future Dib"). Likewise there are a few time skips that remain unacknowledged.
"There was a time-warp or something." —Sizz-Lorr
Solar CPR: The Planet Jackers transport planets so that they can drop them in the sun of their own home planet, to prevent it from shrinking away.
Space Trucker: The Planet Jackers are quite reminiscent of long-haul truckers.
Spanner in the Works : A small chain of it. ZIM is the spanner in the works to the Irken Empire, ruining Operation Impending Doom I, killing the Almighty Tallest, destroying part of the Irken fleet with Mars, and countless other failures such as forcing Tak to have to work as a janitorial drone. GIR is often the spanner in the works to ZIM's plans, however idiotic they may be. And to top it all off, a spanner (or spanners) in the works for the Irkens (or a member of La Résistance, or just a slave really pissed at the Irkens) is sending machinery meant to help invaders to ZIM, and malfunctioning machinery sent by the Tallest just to kill him to Invaders that are actually doing their job.
It's very rare to see the word "squeedlyspooch" spelled correctly in an Invader ZIM fanfic. Because of this, there are innumerable misspellings of the word, but the most common are "squeedily-spooch", "squeedilyspooch" and "squeedly spooch".
"Darkbooty" vs. "Darkbootie" is also an example, as is "GIR" vs "Gir" and "MiMi" vs "Mimi".
Some disputes have arisen on the issue of people or items originating from planet Vort — "Vort/Vorts" versus "Vortian/Vortians". The latter term never made it into production, but appeared in at least one script ("The Trial").
Stylistic Suck: In an ironic bit of What Could Have Been, the writers wanted to do a bit in the last produced episode that retroactively "introduced" the planned character Minimoose by having him crudely pasted into old scenes as if he'd been there all along, but the idea was scrapped for time — yes, an intentionally crappy montage had to be cut for the amount of time and effort it would have taken to make it look bad on purpose.
Tallest Red: I was curious to see when you'd shut up on your own, but it's been three hours now, ZIM. THREE HOURS!!
Superior Species: Provides the actual page quote. Although his mission is to blend in with Earth, ZIM hilariously can't resist rubbing it in everyone's face how far more advanced and superior the Irkens are.
In "GIR Goes Crazy and Stuff" and "ZIM Eats Waffles", ZIM is shown to have a human child captive in order to experiment with the happiness receptors in the child's brain. As a result, the child is compulsively happy. The child's name? Nick.
Third Person Flashback: Lampshaded. ZIM remembers escaping from Frycourtia, and Sizz-Lor coming in and swearing to recapture him. Back in the present, Sizz-lor asks how he can remember that last part if he already left. ZIM doesn't have an answer.
Timey-Wimey Ball: Lampshaded and discussed by ZIM and Sizz-lor after Sizz-lor describes how he spent twenty years on Foodcourtia even though ZIM only left a year or two ago. Sizz-lor tries too pass it off and ZIM dosen't seem convinced by it.
Transplant: Ms. Bitters and the Abductors were major characters in Jhonen's comic Squee!, though neither had names. Two Vortians also appear as rivals of the Abductors.
True Meaning Of Christmas: Dib actually does effectively shame the mob on Christmastime by expounding on it and urging them to go home and spend time with their families. It holds for about five seconds before ZIM shows up as the "Easter Platypus" and turns them against him.
Unexplained Recovery: Is a Running Gag for poor Skoodge... First he was sent to Blorch, home of the slaughtering rat people, for being the shortest Invader of Operation Impending Doom II. When he actually did conquer it, the Tallests still didn't like him and launched him out of a cannon. This still didn't stop him from making an appearance in "Hobo 13", where his remarkable recovery was Lampshaded and handwaved:
ZIM: Skoodge? I thought the Tallests killed you! Skoodge: Yeah, but I'm okay now.
Unwanted False Faith: In "Attack of the Saucer Morons" ZIM somehow fails to see the benefits of dozens of worshipers and instead has to escape from them.
Inverted, given that ZIM is a Villain Protagonist — Dib occasionally gets episodes entirely dedicated to himself such as "Battle-Dib" and "The Sad, Sad Tale of Chickenfoot" where ZIM does not appear at all.
Virtual Reality Interrogation: A variation is present in an episode where Zim puts Dib in a virtual reality where he gains ultimate power and uses it to defeat the Irken and become a major celebrity just so he could get Dib to confess that he threw a muffin at him during lunch.
Wacky Sound Effect: Lots. There is a specific sound effect for stupid people straining their brains.
The Walrus Was Paul: Jhonen Vasquez decided to celebrate the "one month only" rerun of the show in March 2010 by giving an Invader ZIM "fact" each day in his blog. All of them devolve into very, very sick tall tales. Considering he rails against the misinformation about the show and its circumstances on the first post, it's not hard to interpret this as his attempt to outdo his own fanbase at bullshitting.
ZIM: Is that Irken equipment you're using? That's Tak's ship you're sitting in, isn't it? Dib: Yes it is, ZIM! It fell from the- ZIM(yelling): Isn't it!?! Dib(also yelling): I said it was! Man, you have a problem with listening, ZIM! ZIM: ISN'T IT!?!
Yank the Dog's Chain: "Dib's Wonderful Life of Doom" is all this, but "Vindicated" is probably worse.
You Can Run, but You Can't Hide: Dib says it to ZIM, or rather tries to say it but just winds up contradicting himself. ("You can hide, but you can't.... hide!") In his defense he was seriously brain damaged by that point.
Zombie Gait: A mall security guard sends a horde of zombies after ZIM. He is initially scared, but soon realizes just how useless they are as they fall over each other and are completely incapable of harming him.
Imma sing the Doom Song now! DOOM DOOM DOOM DOOM, DOOM DOOM DOOM DOOM! ♪