One year ago this week, CBS canceled Zoo and broke my heart.

It’s almost as hard to describe exactly what Zoo meant to me as it is to describe what Zoo even was, period. But let’s give it a shot: The TV adaptation of James Patterson’s novel of the same name ran for three head-spinning seasons on CBS, quietly growing from a weirdo procedural drama about a global animal uprising to a completely, gloriously ludicrous dive into a post-apocalyptic world plagued by sterility and bloodthirsty hybrid beasts.

From its premiere in 2015 to its untimely death in 2017, every new episode of Zoo brought forth a new adventure that seemed determined to top the last. “Renegade zoologist” Jackson Oz (James Wolk) and his merry band of outcasts — including girl reporter Jamie (Kristen Connolly) and salty scientist Mitch (Billy Burke) — raced to save the planet from the animal virus. Together, they fought killer bees, bulletproof bears, kamikaze bats, and one particularly memorable sloth that caused earthquakes with its every languid yawn.

The series began as a decent enough distraction. But by the time its final credits rolled after a jumbo jet burst through a blockade that was holding a ferocious tidal wave of vampiric hellbeasts at bay — thus setting up a cataclysmic showdown that never came to be — Zoo had become a surreal goddamn masterpiece.

During season 3 in particular, as other, supposedly more “prestige” shows piled up on my DVR, Zoo became a top priority in my crowded TV viewing schedule. The real world was becoming ever more frightening, and television seemed to be following suit. But I could always count on Zoo to deliver consistently bananas entertainment with a hefty wink, and to keep my jaw dragging along the floor in astonished glee. Sure, other TV series might have boasted such things as subtle dialogue and narrative coherence. But did they ever tell a story about a 60-foot-long invisible snake? No, no they did not.

Suffice it to say, the moment when CBS canceled Zoo last October was devastating. Having become accustomed to a weekly dose of pure nonsense, I wasn’t ready to let go of my most precious TV weirdo.

So I didn’t.

Instead, I reached out to some of show’s creative team to get some post-cancelation anecdotes and quickly ended up with an avalanche of insight from many of the writers, producers, directors, and actors who made Zoo such a ridiculous joy to behold. Much to my delight, every single person I talked to couldn’t stop gushing about the pure fun of making a show so unhinged, so delightfully detached from both reality and decades’ worth of established storytelling conventions, as my beloved Zoo.

“[We thought] ‘let’s just throw out the playbook as much as possible,” recalled showrunner Josh Appelbaum, who co-created Zoo alongside his three producing partners Andre Nemec, Jeff Pinker, and Scott Rosenberg. Collectively, the team’s past credits comprise a vast and varied resumé, from Alias to October Road to Mission Impossible: Ghost Protocol. But when it came to Zoo, Appelbaum said, they decided to purposefully flout all of those past projects’ “rules.”

“Our mantra was always, ‘What’s an idea that could ONLY be done on Zoo?’” said writer Nicole Philips, who joined the show in season three, when it flashed forward 10 (!) years to reveal a dystopian future. “I knew an idea had legs when I couldn’t pitch it without smiling and saying, ‘How cool would it be to do THAT?’”

So in that spirit, whether you watched and loved Zoo as I did, or (more likely) you have no idea what I’m talking about, please enjoy the following five behind-the-scenes tales about how one of television’s most charmingly unhinged thrill rides came together.

1) Zoo found its groove thanks to an elevator full of rats

It may seem weird to kick off this celebration of Zoo’s life with, y’know, an elevator full of rats. But we have to start somewhere, and according to co-creator and eventual showrunner Josh Appelbaum, Zoo really did hit a turning point several episodes into the series by stuffing an elevator full of (virtual) rodents and unleashing them into a hallway in a Shining-esque tidal wave of hissing misery.

But before this hyperbolic moment sold the Zoo team on the show’s potential for ridiculous greatness, the writers had been trying to toe a much more serious line, somehow prizing realism on a show that, again, revolves around an animal uprising. That meant they only used animals when they could get actual live creatures on set.

“In the first season, Jaws was a big reference point for us, and what was great about Jaws was the slow burn; you don’t see the shark until the end,” Appelbaum told me. “That’s what [we thought Zoo] should be.” As season one continued, however, the writers’ perspectives started to change. Eschewing CGI animals for live ones was proving more limiting and costly than expected, and the sheer fun of their source material’s “animal uprising” premise was getting lost in dreary stories about corporate espionage.

So for Zoo’s eighth episode — beautifully titled “The Cheese Stands Alone” — the series tried something a little different. It abandoned any semblance of realism and had its characters fight back a teeming horde of frantic rats with a flamethrower. According to Appelbaum, that’s when he knew they were onto something. “‘We should just be doing three scenes like that every episode,’” he recalled thinking at the time. “‘Why are we depriving the audience of rat elevators?!’”

And then came the clincher, courtesy of an unexpected and crucial source. “Eventually, it was James Patterson [pitching in as an executive producer] who said, ‘What the hell is it with this slow burn? What about a burn burn?’” Appelbaum said. “And he was fuckin’ right.”

And lo, Zoo decided to lean into its chaos and unleash some happily nonsensical hell.

2) A polar bear once let her jealousy compromise her Method acting

In season two, Zoo would set about phasing out live animals entirely in favor of using all CGI animals, all the time — the better to stage more outlandish setpieces. But before that policy went into full effect, the team tried to stage a polar bear ambush in the season two premiere, “The Day of the Beast.” As written, the scene involved filming a single polar bear, with the intent of digitally manipulating the animal into a bloodthirsty pack.

“I remember getting the script and thinking, ‘So I have to do a bear-mauling sequence on the heels of The Revenant. How am I going to do that?!” said the episode’s director Norman Buckley.

With some fastidious planning and careful choreography, Buckley and the crew eventually managed to get the bear to do almost everything they needed it to do — with one unexpected wrinkle.

“The polar bear was apparently a female who was very attached to the male trainer, and kind of thought he was her boyfriend,” actor Kristen Connolly, who played intrepid blogger-turned-billionaire spy Jamie, told me. “There were a lot of rules. You couldn’t look at the trainer directly. I think she [the bear] tolerates the man’s actual wife, but only barely.”

Thankfully, lots of patience and (as everyone involved emphasized) respect for the animal on behalf of the Zoo cast and crew ensured that everyone made it through the scene without exacerbating anyone’s jealousy issues. And even though it was moments like these that made the show’s switch to CGI ultimately feel quite practical, there was still at least one more real life animal star waiting to grace Zoo’s set ...

3) The sloth yawn heard ‘round Zoo’s world

Just about everyone who watched or worked on Zoo can agree on at least one point. Like the elevator full of rats before it, “the sloth,” as actor James Wolk put it, “was a turning point.”

The creature in question appears in the fourth episode of season two. He spends most of his time hanging from a branch safely encased in a glass tank and appears to be nothing more than your typical slow-moving, adorable mammal. But the role he was playing was far more nefarious — and more blatantly ridiculous — than anything Zoo had attempted up to that point. You see, this sloth was no ordinary sloth, because this sloth’s yawn could cause earthquakes.

As Appelbaum tells it, the writers’ initial idea was to build this plotline around a howler monkey or a “gnarly fuckin’ hyena” — any animal whose already shrill voice could have mutated, within the Zoo universe, to become a devastating weapon. But at that point in the show’s run, the show was still trying to use real, live animals on set whenever possible, a hyena was unavailable, and the creative team decided to go in a bit of a different direction.

“We started pitching ideas about the slowest and quietest creatures on earth,” writer Matt Pitts said. “[Pitts’s co-writer] Melissa Glenn pitched a sloth and we all fell in love with the idea.”

Well, okay — not all of the writers’s room was immediately on board. “I was not a fan,” producer and writer Bryan Oh admitted, though he was laughing as he said so. “I just kept trying to picture what this would look like. A sloth?”

“That pitch sparked a massive amount of debate around the writers’ table,” said writer Carla Kettner. “There was a real philosophical split between Team-No-Effing-Way-Could-That-Happen and Team-Why-the-Hell-Not.”

In this battle — and, it would turn out, almost all subsequent ones — Team Why-The-Hell-Not won out. “It ultimately was better for the vibe of the show continuing on,” Oh conceded. “That sloth embraced what the show ultimately became.”

But the windfall of the sloth idea itself isn’t all there is to this iconic Zoo moment. At one point during the characters’ frantic search for the animal, they capture a four-star general (played by Peter Outerbridge) and interrogate him to find out the sloth’s whereabouts. When he refuses to answer, Jackson takes a breath, narrows his eyes, and fully backhand slaps the general across the face. “Where’s the sloth?” he seethes, straightening up with righteous fury.

Even after having seen everything that was then still to come, these three seconds comprise Zoo’s most perfect moment — and, as I learned while reporting this story, they weren’t even planned.

Shortly after the show’s cancelation, writer/producer Jay Faerber tweeted at Uproxx’s Brian Grubb (the only person on this godforsaken planet whose love for Zoo rivals mine) that Wolk’s slap was not, in fact, scripted. I later confirmed this fact with Pitts, but to truly understand the situation, I knew I had to talk to the slapper himself.

When I (politely) confronted Wolk on the phone about the possibility that he might have gone wildly off-book, he insisted I stay on the line while he thumbed through several old Zoo scripts to prove me wrong.

“That can’t be right…” he mused, audibly poring through years of outlandish twists and turns to pull this particular memory from the stack. His confusion was genuine; as Connolly put it, “Jimmy” improvising a slap, “out of all people,” was an unexpected twist.

But several minutes of mumbling through sloth drafts later, Wolk was forced to admit the truth: not a single script he could find contained the sassy backhand slap that ultimately made it to air. The actor took a couple seconds to process this information — and then burst into incredulous, delighted laughter. “I guess I needed a reason for him to listen to me, right?” he said. “I mean, when you’re talkin’ sloth, you just gotta do what feels right.”

So, luckily for us all (except perhaps Outerbridge), that’s exactly what he did.

4) The One Where the Gang Fights an Invisible Snake

Once Zoo accepted that a sloth could send shockwaves through the earth and raised its plots stakes enough that certain humans would slap whoever they needed to if it meant saving the world from a savagely sleepy mammal, there was no longer any limit to Zoo’s lunacy. The second season ended with the gang rounding up a herd of mythical creatures including the earthquake-inducing sloth, an ice-breathing lizard, and a sabertooth tiger. (A sabertooth tiger that had somehow survived extinction all by its lonesome on some far-flung island, patiently waiting for an opportunity to save the world.)

But our intrepid heroes somehow still got outsmarted by a shadowy cabal of totally new human enemies who, in the very final minutes of the season, released a toxin that sterilized the entire planet. “Originally we wanted the gas to kill most of the population, but the network thought that was a little too grim,” revealed Faerber. And while this twist might sound impossibly huge, just remember: this was Zoo. As Faerber put it, “that was our compromise.”

I’ll admit that I was skeptical about how on Earth the show could possibly pull off the Children of Men-style turn. But I shouldn’t have doubted Zoo’s powers of persuasion. Deciding, as always, to go big rather than go home, the series revealed on its way out of the season that the next one would take place a full decade later.

Thanks to a combination of the show leaning into its own absurdity and the very real threat of a 2017 TV writers’ strike accelerating the show’s production to a level approaching hyperspeed, Zoo’s third and final season was without a doubt, the most entertaining season of any single TV show I watched in 2017.

In the not so-far-off future, Wolk’s character Jackson not only discovered an evil sister and a long lost song he never knew, but the fact that he could, if he concentrated real hard, control animals with his mind. Jamie the former blogger become a billionaire author slash undercover spy. A katana-wielding “croctopus” overtook an airplane’s controls, a flock of giant vultures dive-bombed New York City, and a blood sample from a rampaging hybrid rhino-mammoth grew into an unidentified fetus. Zoo was officially off the rails, and bless it.

Cleary, Zoo never lacked for imagination when it came to its creatures of the week. But when I asked the creative team to name their favorite animals and/or hybrids from their time on the show, the most popular answer (aside from the sloth) was the 60-foot-long Peruvian invisible snake, because read that phrase again: They wrote an episode about a 60-foot-long Peruvian invisible snake.

What’s more, the downfall of said snake came about when it made the mistake of swallowing Jamie whole, at which point she triumphantly sliced her way out with a sword.

“I found out about it before the script came out because our wardrobe team came to me and said, ‘What kind of shoes would you be most comfortable wearing climbing out of the snake next week?’” Connolly recalled. “And I was like ‘... what?’”

I’m happy to report that the resulting sequence is exactly as beautiful and silly as it sounds (alas it is not on YouTube). In the future, when aliens come asking for a peak example of human ingenuity, I will point them in the direction of Jamie slicing and smirking her way out of from the belly of an invisible serpent.

“I could work on television for a thousand years,” said Zoo season three writer Geoff Tock with a sense wonder, “and I’ll never get to pitch something like that again.”

5) The gravity-defying car stunt that proved impossible to beat

For my money, there was one scene in which the final season of Zoo topped itself for good, a scene that is forever burned in my memory for its ridiculous audacity. Halfway through the season, the world is in danger of being overrun by giant vulture hybrids whose favorite mode of attack is to throw themselves down at their prey with the precision of an Olympic high-diver. (Look, you’ve already read this far; just go with it.)

To avert disaster and lure the vultures away from the general populace, our heroes decide that there’s only one thing to do: They must trick the beasts into diving into an active volcano.

To achieve this, they throw a homing beacon into a Mustang and push it out the back of a plane — not realizing there’s a man hiding in the trunk. It’s a stunning moment whose only possible comparison point lies in the Fast and Furious franchise, if that franchise were to fully commit to releasing itself from the accepted bounds of time and space.

Look, I could sit here and explain every piece of that sentence, but rest assured: Knowing all the ins and outs of this Mustang/volcano/murderous bird sequence isn’t at all necessary to appreciate its bonkers brilliance. In fact, all you really need to know about how Zoo approached its storytelling is that this isn’t even a season-ending cliffhanger; it was the beginning of the episode.

“It was just like, ‘fuck it, that’s the opening of the show,’” laughed Appelbaum. “‘Let’s build the episode from there and see what happens.’”

As Tock’s writing partner for the episode, Gregory Wiedman, revealed, “the original idea was even crazier. The volcano erupting was going to be the first in a series of global events that was going to eventually terraform the planet to be more suitable for hybrids.” In fact, he added, “[it became] a general rule for any big, crazy story beat on Zoo [that] the first version was probably twice as nuts.”

So while it’s still hard for me to explain exactly why and how I loved Zoo as much as I did, I am compelled to tell you that these 3,000 words or so are merely the tip of the iceberg. I just hope you can understand that at the heart of my devotion to this weird and wonderful show is the fact that it was unafraid to embrace its most ridiculous self. In a TV world overflowing with bland franchises and self-serious meditations on humanity, it was a genuine joy to sit down every week to watch a completely ridiculous, unpredictable show have so much fun.

As Wolk told me with an audible grin in his voice: “When things got as wild as they were, it was like a constant mind blow. It was like, ‘Of course there’s going to be a car into a volcano followed by birds. Let’s do it.’”

The first three seasons of Zoo are currently available to stream and gape at in slack-jawed wonder on Netflix.

Correction: An earlier version of this story mischaracterized one of Zoo’s fictional creatures. It was a katana-wielding “croctopod,” not a knife-wielding octopus.