‘Common Side Effects’ Isn’t What You Think It Is

“In a mad world, only the mad are sane.”

Stated by the court jester Kyoami in Akira Kurosawa’s 1985 “King Lear” adaptation, “Ran,” the above quote has become increasingly, alarmingly apt during the agonizing initial weeks of 2025. Suddenly, all the worst-case scenarios are coming true. The most unpopular president this century is dictating tyrannical violations of the U.S. Constitution. American democracy has been hijacked by a one-man plutocracy. Luka Dončić is a Los Angeles Laker.

All this reframes the extremists of yesterday as the rationalists of today. In a world where the megaphone is controlled by unmistakable morons, maybe the so-called kooks and crackpots are our new voices of reason. Maybe the nutters know something we don’t.

Enter Marshall Cuso (voiced by Dave King), a bearded guy with long hair, cargo shorts, and a shirt that’s never once been buttoned. Introduced with his globular belly brushing up against the microphone stand as he decries the environmentally unfriendly practices of a pharmaceutical company — while cradling a frail green plant — Marshall looks like your classic fanatical hippie. Minutes later, after he’s been tossed out of the shareholder meeting, he picks up a pigeon off the sidewalk and snaps its neck. Woah! Yikes! Are we sure this guy’s just a free-thinking flower child and not some sort of sicko?

We are, and he’s not. Despite all ostensible evidence to the contrary, Marshall knows exactly what he’s doing. His appearance is dictated by how much time he spends outdoors, for his job, studying plants. He’s a shareholder in the pharma company, so he had every right to speak at their shareholder meeting. And the pigeon? As soon as he kills it, he revives it, sprinkling blue specks onto its beak in order to show his friend exactly how powerful his most recent discovery can be — all so they can work together to spread its healing properties the world over.

Sounds like someone you might want to hear out, huh?

“Common Side Effects,” the new animated series from Joseph Bennett (a co-creator of “Scavengers Reign”) and Steve Hely (a writer on “Veep” and “The Office”), is a throwback conspiracy thriller following Marshall, whose discovery of the Blue Angel mushroom makes him the target of mysterious governmental forces, big pharma, and envious entrepreneurs. They all want to exploit the rare fungus’ miraculous regenerative properties for their own gain. Marshall wants to grow the fungus in order to help heal the world. It’s a classic David vs. Goliath action-adventure story, except… well, it’s also kind of a comedy? And a gravely realistic drama? And an existential science-fiction saga?

Every time it feels like “Common Side Effects” has settled into one genre or another, it pivots — never enough to disavow the appealing elements that make the Adult Swim original series so easy to fall for, but just enough to make you question if you’ve seen something quite like this before.

And you can tell as much within the first five minutes. Immediately after introducing our lead protagonists Marshall and Frances (Emily Pendergast), the premiere shifts to our two other leads: DEA Agents Copano (Joseph Lee Anderson) and Harrington (Martha Kelly). The powers that be have identified Marshall as a priority target, and they need to assign their best officers to get rid of him. The tone is serious, the vibes are ominous, and then… cut to Agent Copano, chilling in his car, listening to Harry Belafonte’s infectious, jubilant, Caribbean hit, “Jump in the Line.” He turns up the music. His partner, ordering a hot dog at a cart across the street, hears it in her earpiece, and both sets of shoulders start to shimmy to the beat. Soon, the car is shaking as they sway to the beat, and “Common Side Effects” evolves beyond its root genre as a conspiracy thriller. It’s fun! It’s silly! It’s “Shake, shake, shake señora!”

But even though the agents’ happy-go-lucky behavior serves as a punchline (could these two dancing fools really be the best the department has to offer?), they most certainly are not. Over the first four episodes, “Common Side Effects” fleshes them out as people and partners. They’re not stupid or incompetent, even if Copano, especially, can be forgetful and fanciful. They’re not mere tools of the man, even if they do hide behind the safety of following orders from time to time. They’re not romantically involved, even if they do share an enviable, rock-solid rapport.

These DEA agents are tasked with a mission of unparalleled global importance, but they can still throw impromptu dance parties, flirt with mycologists, and waste time making redundant coffee runs because they don’t know the real reason they’re tracking down Marshall Cuso. The contrast between the significance of their role in the grand scheme of things and their gleefully carefree behavior is just one of many astute disparities in “Common Side Effects.”

Take the converse color palettes seen in the splendid animation. Scenes centered on corporate stooges or government administrators are cast in bland browns and sickly yellows, while moments based in nature or the afterlife are bursting with bright blues, pinks, and greens. Whenever we’re put in the perspective of someone being saved by a magic mushroom, the imagery becomes as lush and sparkling as the Blue Angel itself.

‘Common Side Effects’Courtsy of Adult Swim

Then there’s Marshall himself. In the brief time we’ve known him, he’s been kicked to the curb, shot at with machine guns, hit with a truck, and otherwise attacked at every turn. He’s been given every reason to be angry, frustrated, and cynical, toward the specific people coming after him and the world at large. Instead, he’s kind, forgiving, and hopeful. He’s always looking to help people — giving up his precious few remaining mushrooms to save a stranger in a car accident or revive his high school friend’s mother with dementia — and he’s always asking others for help. He believes in people, and his belief buoys a series that could have easily painted Marshall’s fellow humans in a less forgiving light.

Better still, you can see the series’ fondness for humanity in what New York Times’ critic James Poniewozik called “appealingly digressive” storytelling. Every few minutes, in pretty much every scene, something weird happens that’s unrelated to the central plot. A barista announces an order for “Gegory” and Marshall stops explaining how he survived a plane crash to wonder if that’s actually the patron’s name, or if the barista mindlessly misspelled “Gregory.” (They did not.) Agent Harrington bails on a working dinner to go on a date with Amelia (Shannon Woodward), and when Agent Copano says, “Amelia Mushrooms? The mycologist?” Harrington knowingly replies, “I’m making it complicated.” When Frances gets a frantic call from Marshall, who’s looking for a safe place to talk as he flees from the cops, she turns around to see her boyfriend, Nick (Ben Feldman), awkwardly reeling in a fish via his VR headset. Then he asks her to pick up some cheese — the “good” cheese — while she’s out.

These little digressions won’t please plot purists, but they’re absolutely central to what the series is about. Each random aside and unexpected focal point helps develop the characters, fleshing out Marshall, Frances, Copano, and Harrington beyond their function in the narrative. Our lives aren’t only defined by what we do — for a living or to survive. They’re defined by our interests, our eccentricities, and our peccadilloes. Diverging from what needs to be done may be frivolous and incidental by definition, but it’s also often what makes life worth living.

No one has to bring their coworker a coffee every Thursday, like Harrington does for Capano. It’s not in either of their job descriptions, and it’s inessential to their current assignment. But it’s nice. And nice is reason enough for them to do it, and for “Common Side Effects” to include it in the story. The same can be said about having a beer while watching your favorite movie, or watching your boyfriend look foolish while playing a video game, or dancing in your car in the middle of the day.

Each of these odd little moments is delightfully out of the blue, which helps to balance the main story’s unsettling familiarity. “Common Side Effects” is a conspiracy thriller about a guy no one takes seriously but who just might save humanity. It’s also a comedy (and a drama, with a hefty dose of sci-fi realism) about the fleeting indulgences that make us human. The show usurps expectations for good reason — and for a reason fairly common to classic conspiracy stories: to get us to rethink the way the world works. Hopefully, before it’s too late.

“Common Side Effects” releases new episodes Sundays at 11:30 p.m. ET on Adult Swim and Max.