Invader Zim has always been a unique kind of phenomenon. Upon its release in 2001, the show immediately set itself apart from everything else airing on television at the time. Its bizarre sense of humor, dark subject matter, deranged animation, and artistic style all led to high praise from critics and audiences alike. The series easily stood out among the other cartoons that Nickelodeon had to offer, and consistently pushed the boundaries of what children’s animated programs could be and even look like.
Unfortunately, it was short-lived. With a mere 27 episodes to its name, Invader Zim was canceled only a year later – with declining viewership and budgetary concerns (this was not a cheap show to make) to blame. Despite this, or perhaps even because of its short-lived reign, Zim would go on to reach cult status. A rabid and dedicated fanbase has kept the show alive and well in people’s minds for nearly two decades, long after its sudden cancellation. The show is considered required viewing for any young person who falls in with the “Hot Topic” crowd. It goes hand in hand with The Nightmare Before Christmas and the likes of others that hold a whimsically darker aesthetic than most other things aimed at children.
It is thanks to those annoying, screeching fans (myself among them) that Invader Zim has lived on, returning in comic book form in 2015 with its creator, Jhonen Vasquez, at the helm. Although, the demand for Zim to be given a chance to come back in all of its fully animated former glory continued until Nickelodeon finally announced Invader Zim: Enter the Florpus, a full-length animated film that would bring back the original cast and offer long-overdue closure for fans. The film is currently available on Netflix, but it is nevertheless always a good time to look back at what exactly made the series so beloved in the first place. Let us go through the very best episodes that the cult classic has to offer.
The Nightmare Begins (originally aired March 30, 2001)

There is no better place to start than at the beginning, and Invader Zim’s introductory episode is one of its greatest. The series has always been extremely quotable, and half of those memorable lines all come from this single episode (“It’s not stupid, it’s advanced!”). The Nightmare Begins is an essential moment in animated television history, a perfect entrance for the show’s universe and characters, and an instant place of refuge for any kid that felt different or strange, or just plain insane.
Parent Teacher Night (originally aired April 6, 2001)

Zim’s robot parents are pretty much a one-note gag, but they get their time in the spotlight early on when parent-teacher night comes around and Zim has no choice but to attempt to pass them off as real people for school. Strapping them down and wiring them up A Clockwork Orange style, Zim forces the robo-parents to learn how to behave properly. Of course, all havoc breaks loose during the fated night anyway, complete with nuclear explosions, diarrhea jokes, and some of the best moments from Zim’s teacher, fan-favorite Ms. Bitters.
Walk of Doom (originally aired April 6, 2001)

Zim and GIR go out on the town to test a new guidance chip, but GIR ditches the chip in favor of a cupcake right before they leave. Lost and panicked, Zim drags GIR through town in a vain attempt to get back home. Along the way they encounter the horrors of public transportation, Zim learns not to stare at the sun, the two get chased by police when Zim is mistaken for a bank robber, and finally, the pair wind up somewhere in Mexico. The jokes are rapid-fire and the dynamic between Zim and GIR is at its best here – it is a classic.
Dark Harvest (originally aired April 20, 2001)

Invader Zim was known for its taste of the macabre, sometimes to the point where it stirred up a bit of controversy. While every episode has its fair share of twisted humor and bleak writing, none hold a candle to Dark Harvest. It tops every list of the series most disturbing episodes and was even cited during the trial of Scott Dysleki, a convicted murderer. In the episode, Zim is worried that the school nurse will realize he is not human since he lacks organs. To fix this, he stalks his fellow classmates and steals their organs, replacing them with crude objects and hoarding far more organs inside himself than he needs. The imagery is deeply unsettling, and it is the first time the show leans almost completely into horror territory. It is the series most infamous episode for a reason.
A Room With a Moose (originally aired August 17, 2001)

Zim harbors a grudge towards his classmates due to their mistreatment of him, so one day he decides to punish them by putting together a fake field trip. The kids board a school bus that turns out to actually be a spaceship, which Zim plans to launch through a wormhole and be rid of them for good. There are several dimensions that Zim thinks about sending them (including a dimension of pure itching), but he ultimately settles on a dimension made up solely of a blank room occupied by a moose. Dib is the only one among his oblivious classmates who realizes what is happening, and it is up to him to rescue everyone from their moosey fate. The show’s humor is often thought of as just a combination of screaming and randomness for the sake of it, but A Room With a Moose is a fantastic example of the fact that Zim is more of an absurdist style of humor; the very kind that people love about shows such as It’s Always Sunny in Philadelphia and Rick & Morty. What exactly is so terrifying about the moose is never made clear, but that is the whole joke, among many great ones in this hilarious episode.
Bad, Bad Rubber Piggy (originally aired August 24, 2001)

Zim creates a time portal device that replaces any object in the past with an object from the present that you toss into it. Initially hoping to send a (“What is it?!”) Hunter-Destroyer machine to the past to kill Dib, he instead accidentally throws in one of GIR’s rubber piggies. It still winds up doing the trick – with each piggy Zim and GIR send back to the past, the more horribly Dib gets maimed by them in hilarious ways. The ridiculous framing of this episode is one that can only exist in the Invader Zim universe, and it is a standout that showcases everything unique about the show and what makes it all work so well.
Game Slave 2 (originally aired September 21, 2001)

Gaz is in line for the release of the newest handheld gaming console when a boy named Iggins tricks the salesperson into giving him the last remaining one. Hellbent on revenge and taking back what is rightfully hers, Gaz goes in pursuit of the boy to make him hand over the console. This is one of the only episodes in the series to not feature the titular character at all, allowing Gaz to display her gaming prowess, thirst for righteous vengeance, and overall competence. Her ability to terrorize Iggins, who himself is an ahead-of-its-time representation of misogynistic gatekeeping gamer fanboys, into giving up the console is the best possible display of her drive and fury. There are only a couple of episodes centered around Gaz, but this has her at her best.
Mysterious Mysteries (originally aired March 22, 2002)

Dib goes on his favorite TV show to tell the world about Zim. He plans to share a video that provides evidence that Zim is an alien. An obvious parody of Unsolved Mysteries, this episode is nothing but pure fun. Each character comes on to share their perspective of what is going on in Dib’s video, which the in-universe show presents in dramatic reconstructions. The show quickly goes off the rails, the actors get injured, and the host has a full mental breakdown. It is one of the series’ funniest and most instantly accessible episodes to put on and laugh at (“It has to be better than Pigfoot”).
Nanozim (originally aired April 13, 2001)

Zim shrinks himself down to microscopic size and enters Dib’s body so that he can control it (“Arms… like… Noodles!”), but Dib fights back with some nano-tech of his own. Invader Zim’s animation style was ahead of the curve, seamlessly blending traditional 2D animation with new computer-generated animation to create a unique and mightily impressive look all its own. This expensive technique would be displayed in bigger ways in episodes like Battle of the Planets, but Nanozim was the first to really show it off. The fight between Zim and Dib, and later, Gaz, was the first time the series showed just how good it was at doing exciting action sequences – fully entering the realm of science fiction that would become a constant for it moving forward.
Abducted (originally aired April 12, 2002)

Zim and GIR are abducted by a pair of aliens who kidnap numerous specimens to do experiments on, which mostly just means that they “fuse” things to living creatures – just because. Luckily for Zim and GIR, the two aliens are complete idiots who are totally incompetent at their jobs. Like Mysterious Mysteries, this episode is just flat out hilarious from start to finish. There are few things better than an inspired episode written solely for laughs, and Abducted is a great example of one.
Tak: The Hideous New Girl (originally aired May 10, 2002)

When a new girl at school, Tak, arrives and reads a poem out loud, the class interprets it as a love poem from her to Zim (they are too dumb to realize that it is actually a threat). Zim, wanting to learn more about humans so that he may be better at exterminating them, tries to woo Tak so that she will become his “love pig”. But Tak is revealed to be an Irken invader herself, one with a personal vendetta against Zim and her own plan to take over Earth. This episode, along with The Frycook What Came From All That Space, is one of the rare instances where we learn a bit about Zim’s life before being sent to Earth, and the hints of a larger narrative at play. It is the first time the events of an episode lead into other ones: Backseat Drivers From Beyond the Stars and Dibship Rising. Both of which have Dib attempting to get Tak’s spaceship up and running again. It is the only time we see Zim, Dib, Gaz, and GIR team up for the same cause and one of the few times Zim inadvertently saves the planet instead of destroying it. Tak is a welcome addition to the cast (another reason why the show’s cancellation was so crushing) and her episode carries an almost epic vibe to it, which is something the series would display several times before its abrupt end.
Dib’s Wonderful Life of Doom (originally aired May 24, 2002)

Dib is visited by aliens that give him special powers, which he then uses to finally thwart Zim and save the planet. The episode then goes through Dib’s whole life as he travels the world solving more mysteries and defeating more aliens. A standout moment of the series is when an adult Dib takes on Zim’s leaders, The Almighty Tallest, and the entire Irken armada in a massive space battle that would rival some of Star Wars’ best scenes. It is a very different episode with one of the most incredible payoffs at the end, and it has always remained a favorite.
Backseat Drivers From Beyond the Stars (originally aired June 10, 2006)

Zim’s desperate desire to impress The Tallest comes to a head when he remotely takes control of their ship in order to forcefully bring it to Earth. At the same time that Zim is hijacking the ship, The Tallest fall under attack by a misfit band of rebels who call themselves “The Resisty”. While all that is happening, Dib finds a way to remotely access Zim’s computer to try and wrestle control of the ship himself. Chaos ensues as the four groups each try to deal with one another, and it is one of the best moments of spectacular writing that the series ever managed to pull off. Funny, exciting, and taking place on a large scale, Backseat Drivers is one of the best examples of the kind of potential that the show had, and a good case for why it should have been brought back a lot sooner.
Zim Eats Waffles (originally aired December 20, 2003)

This is the quintessential Invader Zim episode. It is the perfect culmination of all the different elements of the show that make it what it is – all working in harmony. Dib installs a spy camera in Zim’s kitchen, hoping to catch some sort of evidence of the alien’s existence for the world to see. What he gets instead, and what the audience gets to witness for the entire episode’s runtime, is a relatively quiet morning at Zim’s house as GIR tries to get him to eat waffles. It is a glimpse into the life of the titular character when he is not especially up to anything. It is packed with the kind of manic, clever humor that the show is known for. Anytime Zim begins to mention evil plans or something insane happens like a giant flesh-eating squid popping up in the kitchen, Dib contacts his fellow paranormal investigators to get them to witness it. Each time they do though, Zim is back to eating waffles, whatever had been happening already dealt with. It is a hilariously unique episode that feels like something you would expect to see much later in a series’ run, but since Zim never got that luxury, it is a downright miracle that we ever got something like this.