Dave King has always kept one foot in improv and the other in finely scripted chaos. You probably first caught the name on “Parks and Recreation,” or maybe you remember him from stand-up in late-night Chicago basements. More recently, he scored laughs writing and producing “English Teacher” back in 2024. But now, with Adult Swim’s “Common Side Effects,” King doesn’t just write the jokes—he becomes them.
He jumped head-first into voice acting, taking the lead as Marshall Cuso: science nerd, anxiety magnet, and all-around straight man to Frances’ lovable lunacy. Just when you think acting might be enough, King ups the ante. Cue Episode 5, “Star-Tel-Lite,” where he not only steers the character but also pilots the script. It’s a one-two punch that most rarely pull off, especially on a show that’s part wild sci-fi, part adult cartoon fever dream.
Meet Marshall: Blue-Mushroom Mythbuster
Marshall isn’t your typical animated lead. He’s the guy who labels his lunch, reads fungal genome studies for fun, and dodges low-level government agents like he’s allergic to authority. In a show filled with blue mushrooms that cure anything (except good sense), Marshall stays nervous, always half-convinced disaster hides under every lab coat.
That fretting—King says—comes straight from his own playbook. In the cold open of Episode 1, Marshall tells Frances, “I label my lunch, Frances. Nature ignores labels.” King delivers it deadpan, but lets it stretch just long enough for the joke to land. Fans instantly latched onto Marshall, calling him “the anxiety avatar every millennial secretly nurtures,” as Gazettely so lovingly put it.
So, why does King’s Marshall work? Well, for one, King plays him like he knows there’s a joke hiding in every nervous breakdown. He modulates his pitch—a little breathy when Marshall’s scared, then quick and tight when he’s scheming. The guy makes science dorky and heroic in a single, nervous exhale.
When the Booth Isn’t Enough
Here’s the twist: just voicing Marshall didn’t scratch the creative itch. In a blog interview on AdultSwim.com (back in January 2025), King confessed he felt “itchy” to dig deeper into Marshall, especially after the wild events at the end of Episode 4—the infamous, botched DEA blow-up.
Creators Joe Bennett and Steve Hely saw something brewing. They knew King wrote as sharply as he performed. So after an epic late-night rewrite session, they handed him the script keys for Episode 5. Suddenly, King wasn’t just giving Marshall a voice—he was giving him a nervous soul, line by line.
Star-Tel-Lite: Anatomy of a Pivot Episode
Episode 5, “Star-Tel-Lite,” didn’t just move the plot along. It flipped the whole show on its head. Picking up after authorities seized Frances’ beloved basement lab, we suddenly see Marshall, Frances, and all their wacky neighbors in the aftermath—a post-botched-raid world where power flickers, paranoia spikes, and everyone is a little bit fried.
Dave King had the chance to show us all the layers. Marshall confronts neighbor Doug, the power grid goes haywire, and suddenly there’s a new player: Dr. Valecia, voiced with cool detachment by Gillian Jacobs. The episode ditches some of the earlier slapstick and heads in a more thriller-y direction. And, naturally, Flying Lotus drops a score made of analog synths and bleepy dread, prompting one reviewer at Bubbleblabber to call it a “weird mix of dread and dorky wonder.”
King as Writer: Actor Brain, Writer Fingers
So, what’s it like when the man in the booth writes the lines too? King told a packed crowd at a March 2025 WGA West panel, “If a line bruises my throat, it bruises the story.” That’s his whole philosophy. He doesn’t just tap out dialogue. He speaks every line aloud, often recording loose takes while he fiddles with phrasing. Then, if something feels off, he shreds the words until they land naturally.
Think about that: Every nervous Marshall monologue in “Star-Tel-Lite” came filtered through both King’s brain and his vocal cords. The scene where Marshall tries to explain away the blackout, stuttering through “No, see, the electrons—they, um, unionized,” didn’t come from nowhere. King wrote dialogue that fit how Marshall would actually panic, not how a writer thinks panic should sound.
Plus, King loves to tweak sound. Hard consonants pop when Marshall gets scared, but when he’s whispering secrets in the dark, the vowels draw out, pulling us closer. All those choices come from an actor’s obsession with “mouthfeel.”
Behind-the-Mic Rewrites: When Acting Changes the Story
Let’s talk rewrites and banter. King didn’t lock the script and hand it off. Instead, table reads worked as improv jams, with cast and creators chiming in. At one session, the group flagged a joke that landed flatter than uncooked bread. King pivoted and replaced it with a monologue about lost toothbrushes—a rant so perfectly Marshall that it quickly became meme material. Fans photoshopped Marshall into dental hygiene PSAs the next day.
Sometimes King’s own banter with co-stars sticks, too. Frances’ now-iconic line, “I’m dating entropy,”? That was an improv bit with Kirby Howell-Baptiste (Frances). King ran with it, popping it right into the script. This writing-acting feedback loop keeps “Common Side Effects” feeling less like a sterile cartoon, more like a living, breathing—and sometimes twitchy—ensemble.
Ratings, Reviews, and the Fandom Glow-Up
Here’s where things get fun. The night “Star-Tel-Lite” aired (February 15, 2025, confirmed by Adult Swim’s schedule), #MarshallMakesIt trended on Twitter for almost two hours. TrendPop and Twitter API snapshots back up the numbers. King watched fans meme Marshall’s nervous breakdown and Dr. Valecia’s power cut with giddy delight.
Critics jumped in, too. Bubbleblabber praised King’s “actor-tuned ear,” and said “Star-Tel-Lite” proves “Common Side Effects can do conspiracy chills without losing its dad-joke grin.” Gazettely’s rave called it a “pivot episode” where Marshall stops being just a poster boy for mushrooms and becomes the heart of the show’s mayhem.
Ratings? The episode pulled 0.42 million live-plus-same-day viewers according to Adult Swim’s own press site—a high for the season. That spike, coupled with fan art of Marshall hugging a glowing blue mushroom, all but forced Adult Swim’s hand. They renewed the show for Season 2 a whole two weeks early.
Dave King’s Perspective: Living in the Loop
All through this, King lived in a kind of creative loop. He’d write for Marshall, test lines in the booth, then rewrite after hearing himself get tongue-tied. This blend of improv, acting, and scripting is what makes “Common Side Effects” stand out. It’s not every day you watch a show where the voice actor gets to literally tailor the story to his own neuroses.
And Joe Bennett and Steve Hely? They couldn’t be happier. In interviews, they rave about giving scripts directly to actors—especially ones with writing chops. At SCAD’s TV Fest this year, Hely put it bluntly: “When writers act, or actors write, the result is…way less stiff. The good stuff happens between takes.”
Favorite pull quote for posterity: Dave King told the WGA crowd, “Writing for the guy in my own larynx felt like cheating—deliciously so.”
Mic Drop—and Mushrooms
So, what do you get when you let the voice inside Marshall’s head take over the writers’ room? You get an episode that’s authentic, quick on its feet, and snugly tailored to every stammer, groan, and panicked yelp. You get “Star-Tel-Lite”—the episode where Dave King proved it’s possible to be both puppet and puppet-master, creator and creation. And fans, critics, and Adult Swim bigwigs all agree: it works.
Season 2 is coming, renewals are in, and Marshall’s neuroses have never been so beloved. If you’re betting on future TV, put a mushroom on it. And know that somewhere, Dave King is toggling between microphone and keyboard, making sure every line lands exactly where it should—right in the weird, anxious, beating heart of “Common Side Effects.”
