A tiny cartoon seahorse grips a stallion’s hand. Together, wordlessly, they topple around the ocean through kelp and convenience stores, bop around factories manned by fish, and explore the dark alien depths of the deep sea. It’s very beautiful and incredibly weird.

It’s BoJack Horseman.

Even if you don’t watch Netflix’s animated comedy and occasional existential drama — yes, really — you should probably see this episode, anyway.

"Fish Out of Water" is the fourth chapter of the show’s 12-episode third season, but knowing all the ins and outs of the publicity campaign that brought BoJack — the titular horseman — beneath the waves isn’t necessary to appreciate the story. This is a standalone tale, and with BoJack unable to communicate with others, thanks to a diving helmet, it barely includes any dialogue at all.

Even by BoJack’s high — and highly imaginative — standards, "Fish Out of Water" is particularly gorgeous, not to mention ambitious. After spending so much time on land, this literal dive into a new world made the show’s team work overtime.

"I’m so delighted with what we were able to do, "says production designer Lisa Hanawalt, the creative powerhouse responsible for BoJack’s entire aesthetic design. "Everyone knew it was our Fantasia."

Creating the underwater episode meant looking at everything from Looney Toons to Lost in Translation

The underwater episode "kind of came from two places at once," creator Raphael Bob-Waksberg told me during a larger look at the show’s third season. There was the idea of doing a silent episode, which could "really focus on the visual comedy and the visual beauty" of BoJack Horseman.

"Everyone knew it was our Fantasia"

At the same time, the idea of building out BoJack’s world to show the underwater realm that had been mentioned but never explored in previous seasons was something the creative team had been eyeing for almost the entire run of the series, but had never quite been able to crack.

"One night I kind of woke up in the middle of the night," Bob-Waksberg continued, "and was like, ‘Eureka! These two questions answer each other!’"

Still: Deciding to do an entire, silent episode underwater was much easier said than done.

Writers Elijah Aron and Jordan Young tackled the script, which almost took the form of a silent movie. Meanwhile, director Mike Hollingsworth and his storyboard artists Aaron Long and James Bowman used the initial "Fish Out of Water" synopsis to map out how the episode was going to look — not to mention work, period.

"[Sofia Coppola’s film] Lost in Translation was certainly a part of the conversation," Hollingsworth says, referring to BoJack’s inability to communicate with the sea creatures, like a lonely person navigating a foreign country. "But as it came together, it felt more like Who Framed Roger Rabbit?"

And so the team members unleashed their inner "classic animation nerds," drawing from landmark cartoons that managed to tell complete stories without their characters saying much — if anything — at all.

"It was like seeing a cartoon within a cartoon world," Hollingsworth says, "[or] a modern sitcom character in a classic animation environment."

Sequences like BoJack and the baby seahorse’s madcap dash through the taffy factory came directly from chase sequences from the days of early animation. Hollingsworth even threw in a bit directly inspired by "Porky’s Duck Hunt," animating the seahorse baby eating too much sugar and bouncing off the walls just like Daffy Duck does in that 1937 cartoon.

"This episode is really tied into the history of animation in a nice way," says Hanawalt, warmly.

You can also see some of that Looney Tunes influence when BoJack and his tiny new friend fall into the pitch-black ocean depths, where they’re greeted by a cluster of stark, white eyes.

Basically, Hollingsworth says with a delighted laugh, "it’s BoJack Horseman in [Roger Rabbit’s] Toon Town."

Ultimately, though, the episode didn’t come together until the show’s After Effects editing team figured out one seemingly banal detail: the lighting. "Just making sure people could tell it was underwater and not having that be overpowering was a big [challenge]," says Hanawalt. "We didn’t want to just throw a blue filter over everything, because it begins to look kind of muddy."

And so, Hollingsworth says, the After Effects team "put a gloss, a glimmer, a shine on everything." Finally, having tinkered with the blues and greens of the possible filters, they settled on one that was visibly different from the desert hues of BoJack’s Los Angeles life above ground, but not so different that it felt like another show entirely.

"It's kind of like we were making a new pilot," Bob-Waksberg told me, sounding — like everyone I spoke to about "Fish Out of Water" — equally thrilled and floored that the show pulled it off.

Next step: building out a whole new undersea world

For Hanawalt and Hollingsworth, getting an entire episode highly dependent on their visuals meant getting to splash around in a whole new world of characters and jokes that they’d always been dying to do — even as the two acknowledge that their enthusiasm almost definitely meant more work for everyone.

"We have a certain amount of characters we can afford to make, and I really like to push the boundaries," Hanawalt says. "‘We need just one rainbow parrotfish in there. We need an anglerfish. We need a jellyfish woman. Come on, guys!’"

Then there’s the fact that BoJack Horseman — again, an animated comedy about a miserable horse movie star — has one of the tighter show mythologies of any currently airing TV show.

Hanawalt and Bob-Waksberg decided early on in the show’s run that there would be no hybrid animals — a family in season two included a human father and son, and a deer mother and daughter — and that all animals included in the show would be anthropomorphic.

It’s easy for animators and writers alike to forget these rules, which seem deceptively simple. Hanawalt says the show very nearly betrayed itself once when everyone almost missed an animated weathervane someone had drawn with a plain old chicken on it.

So in the underwater episode, there were a few things to consider. The only sea creatures to make an appearance in episodes other than "Fish Out of Water" are dolphin pop star Sextina Aquafina and newscaster whale Tom Jumbo-Grumbo — who, as Hollingsworth is quick to say, are technically mammals that can technically exist outside of water.

Once, though, a script included a quick gag with an electric eel tasing someone. So Hollingsworth asked the producers, eyebrow raised, "Are you cool with what it’s saying about this world?"

"We’re trying really hard to fill this environment out and create a universe," Hollingsworth says now. "If you’re contradicting yourself every other episode …" Here, he trailed off ominously, but the implication was clear: That way lies chaos.

(And yes, the electric eel does make an appearance in the underwater episode, as everyone knows that is where an electric eel belongs.)

But for as much as the BoJack Horseman team thinks about The Rules, there’s still plenty of room for all involved to create fun and silly things for the fun and silly sake of it. "My favorite things to watch are Miyazaki movies where nothing is explained," says Hanawalt. "It’s just, like, ‘Here’s a giant baby, and here’s a dragon,’ and we don’t have to have hard sci-fi to explain why that is."

Fittingly, "Fish Out of Water" builds out its new underwater universe with care, while still leaving space for the cheekiest of winks.

For example: To add to the alienation BoJack feels as the inverse of a "fish out of water," Hanawalt drew influences from Korean graphic design to set the undersea world apart from land. Storyboard artist Long designed an alphabet that mostly looks like the traditional Latin one, with just enough shifted to make you do a double take if you try to read it.

Then there are the new background characters, from sardines in suits cramming into a bus around BoJack to a squid in the hotel bar signing autographs with his own ink. And then there are the rudimentary details of how this world works, like the cars with fins and flippers propelling them along. Though it would’ve been far easier to design one sardine or car and repeat them, rather than a wider swath, Hanawalt almost always decided against it.

"I wanted a variety," she says. "That’s what we have on land, so why not underwater?"

Every frame of "Fish Out of Water" shows just how much thought goes into BoJack Horseman

Talking to Hanawalt, even for just a few minutes, makes clear just how much thought she puts into the show’s every design, from the characters and their clothing, to the furniture and every single surface that could be plastered with a joke. (Keep an eye on any and all BoJack posters, or you’ll miss out on half the show’s fun.)

Take, for instance, the tiny seahorse who accidentally ends up in BoJack’s care, despite BoJack arguably being the last (horse)man who should be entrusted with the care of a newborn.

When Hanawalt describes the seahorse as "heartbreakingly cute," you might think you know what she means, since okay, the kid is cute. But Hanawalt’s thought about this guy a little longer than you, and so the seahorse was designed specifically to evoke a particularly strong feeling in BoJack.

"It looks a little like Harper, BoJack’s imagined daughter from his drug trip in the first season," Hanawalt says. "I wanted to very subtly call back to that design, because BoJack has such a strong connection to this baby that happens very quickly, so maybe there’s a little bit of that in his subconscious."

It might be this kind of detail that led Hollingsworth to tell me — with an audible grin — that they’re "far too precious with this show."

But it’s also the kind of thoughtful and deeply felt detail that makes BoJack Horseman as affecting as it is, in all its bizarro glory.

All three seasons of BoJack Horseman are now available to stream on Netflix (but if you got to the end of this article and haven’t seen any, you might as well go ahead and watch episode four of season three, stat).

Corrected to reflect that the storyboard artist responsible for the underwater alphabet was Long, not Young.