Gary Larson’s The Far Side will always be on my comedy Mount Rushmore. This legendary strip, which ran from 1980 to 1995, is fondly remembered for its clever humor, bent sensibility, biological diversity, and cow-centric comics.

But let’s take a moment to appreciate Larson’s ducks. Oh, what ducks they were!

I’ll never forget the cartoon showing a sad, paranoid office drone with the caption “Anatidaephobia: The fear that somewhere, somehow, a duck is watching you”—as a tiny duck looks on from another building. Larson tapped into a more universal fear when he penned the comic with this caption: “Suddenly, Professor Liebowitz realizes he has come to the seminar without his duck.” We’ve all been there.

My favorite Far Side cartoon also features a duck. This is the scene: As a boat sinks in the background, a drenched, labcoat-wearing man stands on a tiny island, having just swum to shore. He is confronted by a duck, who has this to quack:

“So, Professor Jenkins! … My old nemesis! … We meet again, but this time the advantage is mine! Ha! Ha! Ha!"

For my money, that’s the best Gary Larson joke.

In The Prehistory of The Far Side, Larson discussed this comic, saying, “Personally, I enjoy cartoons of this type because they lack the obvious ‘cymbal crash’ at the end of the punch line.” Me too. Ever since I was lucky enough to see a student performance of Waiting for Godot at SUNY Fredonia about 20 years ago, absurdist humor has been my favorite kind. There’s beauty in a perfect punchline, but there’s also beauty in using a joke to open up space that allows the audience to fill in the blanks. This kind of joke may not immediately strike your funny bone, but it will seductively and comically massage that funny bone for a longer time.

This particular comic also reminds me of comic books, where the absurdity of spandex-clad heroes fighting crime is one-upped by the absurdity of such battles going on forever (or at least since the ‘30s for Batman and Superman). Larson evoked the superhero world when he wrote, “What kind of a sordid, bizarre past a scientist and some duck could possibly have is for anyone to surmise, but I enjoyed the drama in suggesting that, once again, their lives have become entangled and a new chapter is about to be written.” Sounds a lot like Superman and Lex Luthor, Thor and Loki, or Batman and the Joker, doesn’t it?

Think of the history between two long-running archenemies, like Spider-Man and Dr. Octopus, who have clashed hundreds of times since their debuts in the early sixties under creators Stan Lee and Steve Ditko. At one point, Octopus almost married Peter Parker’s Aunt May, which would have made him the creepiest uncle ever. In another story, the metal-tentacled menace develops arachnophobia, due to a particularly vicious beating by Spidey. Doc Ock was the sole highlight of the unbelievably horrible movie Spider-Man 2, during which I cheered for this vicious villain to murder everyone in the world, including me, just to stop the pain. In a current storyline, Dr. Octopus has successfully switched minds with Spider-Man, becoming the so-called Superior Spider-man, as penned by Dan Slott. (Spoiler alert: This story line is whacked, absorbing, hilarious, and awesome.) The Spidey-Ock history is rich, tangled, silly, and epic: just like what I imagine has been doing down between Larson’s duck and professor.

Who’s the good guy? Who’s the bad guy? Professors are usually eviler than ducks, but the duck is the one cackling like a supervillain. This duck may have escaped from Jenkins’ lab. Both might have been in love with the same chicken. Perhaps both Jenkins and the duck have been battling each other since World War II, like Captain America and the Red Skull. Maybe they were lab partners who cooked meth together: the Walt and Jesse of the comics world. Maybe their brains were switched, like the current Spider-Man situation, which would explain why the duck cackles and gloats but Prof. Jenkins is silent. Would the next panel be the professor saying “Quack”?

Facilitating this kind of speculation is an underrated and underutilized power of jokes. Most jokes are a closed loop. “Take my wife” sets it up and “please” shuts it down. Boom. Joke over. This Larson comic is a reminder that jokes can suggest things without naming them, opening up instead of closing off. In these cases, a joke is more than a little verbal machine that surprises you: it’s a portal to another world.

This isn’t the only Larson cartoon that opens up such huge, evocative, preposterous territory. The cartoon with the caption “Scene from Return of the Nose of Dr. Verlucci” depicts a crack of lightning, a disembodied nose in a doorway, and a man proclaiming, “Egad! It’s the severed nose of Dr. Verlucci—returned from the grave on the anniversary of the night we all betrayed him!” In another, two butterfly collectors confront a black-clad peer, and one says, “Egad! It’s Professor DeArmond—the epitome of evil amongst butterfly collectors!” (Obviously, Larson loved the word egad, and who can blame him?) I’d love to know their backstories, and I can by inventing them.

In fact, I like to think Dr. Verlucci, Professor DeArmond, Professor Jenkins, and even the duck-less Professor Liebowitz all teach together in the same Department of Evil. That almost makes me want to go back to school.

In other words, “Quack quack.”