Common Side Effects Took a Different Kind of Mushroom Trip

Spoilers follow for the first season of Common Side Effects through finale episode “Raid,” which premiered on Adult Swim on March 30. 

In Common Side Effects, big pharma, the U.S. government, and the health-care industry organize the full weight of their power, influence, and violence against a common enemy: a mushroom that can heal any illness and injury. Shouldn’t a natural product that can cure anything be good for humanity? Not for the powers that be — or for the working-class people who covet the mushroom as a way to get rich, too. Nearly everyone who comes into contact with the mushroom is corrupted by it, and that’s because series co-creators Steve Hely and Joe Bennett weren’t interested in telling a simple eat-the-rich story. They wanted Common Side Effects to feel broader and bigger and more reflective of a world in which the “system” can ensnare anyone.

“We didn’t want this to feel like, There’s one right side, and that’s it,” says Bennett, who also co-created the canceled cult hit Scavengers Reign. “It was exploring all of it — and with a little bit of a focus on our incompetence as a whole, as humans.”

Hely and Bennett rattle off a long list of influences for their series, which they started working on in 2019. The outsider ideologies of mycologist Paul Stamets and ethnobotanists Richard Evan Schultes, Wade Davis, and Terence McKenna informed protagonist Marshall Cuso’s (voiced by Dave King) approach to the natural world and the healing mushroom he finds growing in toxic runoff in Peru. The combination of score and visuals in the nonnarrative documentary Koyaanisqatsi affected how the series edited its animated sequences. The inherent absurdity of real-life pharma ads — including the “so strange” trend of “pharma ads having two old people in two adjacent bathtubs holding hands,” Hely says — guided the bleak humor of any scene involving Reutical Pharmaceuticals. And the tension of thrillers like Michael Clayton and The Fugitive, the pacing of The Big Lebowski, and interviews with retired DEA agents shaped Marshall’s quest and the FBI assault on his forest compound in the season finale, “Raid.”

That titular raid is violent: Most of the mushrooms are purposefully destroyed, sick people are caught in the crossfire, and Marshall’s primary pursuer, Reutical Pharmaceuticals board member Jonas Backstein (voiced by Danny Huston), overdoses on the mushrooms and is stuck in a nightmare coma where he watches his tumor-addled body regenerate over and over again. But in the episode’s final minutes, after connecting in the psychedelic “portal world” where people who ingest the fungi mentally go, Marshall and his high-school lab partner, Frances Applewhite (voiced by Emily Pendergast), agree that the mushroom should be free to those who need it. They team up in deciding to “heal” the actual world, and might have unlikely allies in DEA agents Capano (voiced by Joseph Lee Anderson) and Harrington (voiced by Martha Kelly), whose belief in the morality of their jobs changed as they investigated Marshall. All of that is fodder for a second season, which Adult Swim announced last week, and aligns with Bennett and Hely’s insistence that they imagined Common Side Effects as a hopeful show “reflecting our view of the world, which is miraculous and full of wonder,” says Hely, who previously wrote for and produced The Office, 30 Rock, Veep, and American Dad!. “Inspirations are everywhere and inspiring people are everywhere, and there’s enough to find to keep you going, even in the frequent slog that life can be. We could never have made it, making a show that took this long, if we were pessimistic.”

Mike Judge was an executive producer on this, he voiced Reutical Pharmaceuticals CEO Rick Kruger, and he also gave some input on scripts. Was there a storyline or subplot that was shaped the most by his input? 

Joe Bennett: One good example was when we were working on the pilot and were so precious about the order of the shots. There is a bit where Marshall is on this journey discovering the mushroom. It’s a long sequence that’s pretty silent. The initial version, we had that set up as the cold open, and there was a feeling of, We’re really dragging this out before we’re getting to the punch, and the punch is Marshall talking to Frances. Mike was the first to be like, “You should swap these scenes around. You should go straight in.” It changed the game. You’re going right into Marshall’s personality. You’re setting the tone for the comedy up front, and then you have this slower-paced bit that feels like more of a payoff. He’s always got sage insight.

Steve Hely: As an animator, like Joe, he is really obsessed with this little stuff that you might not really notice, like having the lip motion of the characters be pretty precise. If you didn’t have that level of excellence, the show would feel a little less good. We should mention executive producer Greg Daniels, too. He thinks a lot about treating the audience as intelligent. A character being stupid for no reason, that’s just not gonna fly in Greg Daniels storytelling. It’s more that we’ve learned from those guys over the years than like, day to day.

We’re living in a time when doubt against medical professionals, vaccines, and public health is high. When you were writing, how did you find the line between, We’re not doubting the science, but we are saying that the health-care business is damaging and potentially corrupt? 

S.H.: It’s both less interesting and less accurate to the way the world works, to have evil villains who are cackling and twirling their mustaches, than it is to have people in a system that compounds to have very weird incentives. Everybody in the world can observe that that’s true. A pharmaceutical company that has to report results to shareholders will create a warped system that we can all feel is messed up, even the people that work in it.

J.B.: We also just wanted to make a point of the show not being preachy. We want to tell a compelling story and show both sides and really give dimension to all the characters, even if it’s Jonas or Rick.

Maybe this is just me pursuing my own ideology, but was there a discussion of, “These characters keep recreating capitalist structures, and that is what’s bad”? Because I think about, say, Hildy charging people for the medicine, which felt to me like a suggestion that capitalism is at the root of a lot of these problems. 

S.H.: We often would say the bad guy in the show is the system, and the system isn’t anybody. We’re all participating in it just by being on this Zoom, or by whatever we’re doing. We’re just trying to make a funny show. But the way that the system trickles down and accumulates is absurd and mind-boggling. And humans wrestling with their roles in that system, and where their ethics and their personal compromise lines are — what they consider uncrossable — that’s all pretty interesting.

Within Vulture, we called all the Scavengers Reign creatures “weird little guys.” In Common Side Effects, we get another weird little guy: a humanoid pill creature who shows up in the portal world people pass through after they take the mushroom and before they come back to life. Did you have a guiding visual approach for those “weird little guys”? And I keep calling him the “pill guy,” but I wasn’t sure if you had an official name for the creature. 

J.B.: We don’t have a name, and in Scavengers as well, it was nice to build this whole ecosystem and not have to label things. That felt a little trope-y and overdone, and it was nice that there’s all these things that just exist in that world as part of the world-building. The little guys in Common Side Effects, there was a lot of early exploration. One element was, if anyone takes psilocybin mushrooms, there’s always a feeling of another presence there, or something watching you. It’s neither good nor evil; it’s just kind of there, and there’s some kind of balance. That was part of it. But no, there’s no methodology. It’s just coming out of the noggin. I was trying to think of it as vague and open-ended, and not to get too specific about like, “What’s the gender?” It’s just this weird amorphous creature.

S.H.: It was a lot of fun watching these guys evolve as little drawings Joe was doing. There were various, what are they called, Pokémon evolutions?

J.B.: Yeah, yeah.[[Laughs.]They represent something different each time in that portal world. The fact that they’re not even speaking was very deliberate. Finding that balance — it’s playful, it’s fun, it’s also merciless, it’s scary, it’s a little bit of everything.

I don’t know if you guys are fully aware of how much people love Socrates. From fans, there’s a real “We would die for this tortoise” vibe. 

S.H.: I don’t think that he’s a specific real species, but we took care with Socrates in our role as his creators, and we promise to keep taking care of him.

If Socrates were an animal in the Scavengers Reign universe, what do you think his little twist would be? Each of those creatures had its own unexpected little thing.

J.B.: He can take his shell off and use it as a little life raft, a little boat.[[Laughs.]

The finale includes a destructive FBI raid on the compound where Marshall and Hildy have been successfully growing the mushroom and treating people. How did that sequence come together? 

S.H.: Waco and Ruby Ridge were on our minds, and the way that events like that have a tendency to spiral out of control. Joe grew up in the woods of Georgia and knows about those backwoods places, and we talked a lot about the strange characters you encounter there. You don’t have to be from the rural South; we had plenty of people like that in Massachusetts.

J.B.: Having crazy neighbors that have landmines everywhere — we thought all these little things were a good setup for a crazy, chaotic ending.

S.H.: We thought about the train-wreck aspect of somebody trying to stop something, but the motion’s already underway. The tension on both sides is so extreme that it gets out of hand, and there comes a point where you can’t back down, and then it gets worse and worse and becomes a clusterfuck, as they say in the show.

Was this the most demanding episode in terms of animation?

J.B.: They were all pretty demanding, but the raid, there’s a lot of characters moving, there’s a lot going on. There might not be as many action set pieces as an anime. But the equivalent of a three-minute action set piece at the end of an anime would be, you break that up into a lot of little moments throughout each episode. Instead of it being a fight scene, it’s a really intimate dialogue scene between Copano and Harrington talking. You’re really putting the same amount of effort into that. You get these really subtle moments because of that. There may not be a lot of movement, but there’s a lot of work going on.

S.H.: There was a deleted scene where Marshall, in between the raid and meeting up with Frances, visits a rancher who has an injured horse, and he gives the mushroom to the horse. The early animation work was spectacular, but it was not all that necessary to the plot. We cut it, but it was quite cool.

How much would you say you cut over the season? 

J.B.: There was cutting in the writing, in the animatic. We wanted that flexibility. Even if it gets down to the 11th hour, Steve and I could say, “We’re not feeling it,” then we have the option of cutting it or adding something in. I personally love those impulsive, last-second decisions. They’re coming from somewhere, and I embrace them.

S.H.: The script of that first episode, it was 35 pages at one time; as broadcast, it was 25 pages. That’s a huge amount to cut, and probably along the way to the script, it was 45. It’s painful, because often these are beautiful drawings, and a lot of work is getting cut.

How did you land on the body-horror ending for Jonas after he eats so many mushrooms to try and heal his cancer? Was it always this very gross, birthing-himself process?

S.H.: This is a guy who’s greedy and has given into instincts and aspects of the human spirit that are not the most ennobling.[[Laughs.]It seemed like there should be some reflection of, if you come into a psychedelic experience from a greedy, selfish place, there’s payback on the other side.

J.B.: And making it so everyone has their own tailored version of this experience — the house in Jonas’s world, the hospital hallway, all these things are representative of something that happened in his life that we may or may not get into in season two.

As far as the body horror, I tend to go in that direction. Alan Resnick, a really incredible artist, voices Zane. He has been making art using AI, and it’s these blobs of flesh. That was a big influence, as well as Matthew Barney and the Cremaster Cycle. We were trying to do something like at the end of 2001: A Space Odyssey, where the second that the person’s perspective shifts, now you’re going inside the POV of who they’re looking at, and it’s the same person. You’re going in this weird little spiral, and Jonas is seeing what’s becoming of himself.

We end with Frances and Marshall reunited in Joshua Tree, where the two of you spent some time together while working on the show. What did you want to capture about Joshua Tree as the place where Frances and Marshall are finally on the same page? 

S.H.: I’m wearing my Mojave Desert Land Trust sweatshirt. That is a trippy, interesting, visually stimulating landscape. A person like Marshall, it would be important to him. Seekers of all kinds are drawn to the desert, maybe because it’s so quiet and stark that it seems like, It’s just me out here and God, if he’s there, or she. If I’m gonna hear from them, it’s gonna be here.

J.B.: It feels like a place where someone can escape and really never be found. It was such a prevalent visual motif in the portal world, those boulders and Joshua trees. It only felt appropriate to bring it back at the end.

S.H.: You know the expression “I could see him coming from a mile away”? Out in Joshua Tree, there’s places where you can see someone coming from a mile away.[[Laughs.]For a story of fugitives, that’s interesting. We had an extended scene we cut, of Frances encountering a wandering woman and her kids and her health issues. Even if these cut scenes don’t end up in the show, they inform the world. It makes the world richer, that we at least knew what they were doing in between the times we see them.

We’re talking a lot about psychedelic-drug experiences. Is there anything personal that either of you have experienced in that realm that helped shape the show? 

S.H.: I’ll start, because I’m on public record. I wrote a book, The Wonder Trail: True Stories From Los Angeles to the End of the World, that includes the taking of ayahuasca. I was interested in plant medicines and have tried them. I’m not necessarily an evangelist for them, and I think they can be quite dangerous, in fact, and people put a little too much on them. You’re likely to get out what you bring to it. Joe can answer as lawyerly as he likes.

J.B.: Steve kind of said it. I’m right there with him — not really an evangelist about it, but definitely have felt profound, spiritual experiences from it. I also think there’s a shitty stigma from people who aren’t familiar with that world; they may think of it as only psilocybin and magic mushrooms. And yet there’s so many unbelievable medicinal properties that mushrooms that don’t even have psilocybin have to offer. There are mushrooms that you could buy at a nutrition store, a Whole Foods or something, that are scientifically proven to help reduce tumor sizes and help people going into remission. It’s a real thing, and that was an element to this. Public perception has been sort of Reaganized in a weird way, and become this …[[Laughs.]Steve, if I’m saying anything —

S.H.: No, I love it.

J.B.: It just has a weird stigma to it that I think is wrong. We were also very cautious about common psychedelia tropes you see in movies and shows: tie-dye and wavy lines. This was an opportunity to come up with something completely different. Let’s have this feel separate from a typical mushroom trip.

Adult Swim announced Common Side Effects’s release date in December 2024, the same week Luigi Mangione was arrested and charged with killing UnitedHealthcare CEO Brian Thompson. I have two questions related to that coincidence. First, did the show change after Thompson’s death — were you asked to alter anything? And second, I’m curious if you guys have considered whether people who are interested in Mangione might also be fans of Common Side Effects. 

S.H.: I’ll answer number one first, which is no. The show had already been locked; we were contemplating season-two stuff. We’re thinking about everything and consuming everything and learning everything we can and where society’s at on these specific things. That will probably be all somehow baked into season two. The second question — Joe and I have both had experiences, as every person alive has, with medicine and health care that have been frustrating and aggravating. Just saying the word insurance makes people’s hair stand on end, because how is it that we end up in this state where you’re suffering and pressing “two”? You’re at the most vulnerable, or a loved one is really suffering, and that can be very infuriating. And the event that occurred is connected to that, right? It’s connected to a societal aggravation with something that’s huge, bureaucratic, seemingly monstrous at times, out of hand. Joe and I were picking on that theme a while ago, obviously. The support for Luigi Mangione, the excitement, the fascinated news compulsion around it, is related to the same stuff we were thinking about. It’s all coming out of the same nerve we were touching on.

J.B.: Yeah, there was a raw nerve.

S.H.: I saw on Max a documentary called Who Is Luigi Mangione? that was like, No. 2, and Joe and I were like, “I hope that the people who are watching that are aware of Common Side Effects.”[[Laughs.]