For 12 episodes of comic-book psychedelia on FX’s Legion, Aubrey Plaza has found a way to turn into terror incarnate. She has crawled on all fours, humped furniture, and song-and-danced her way inside characters’ innermost fears, morphing from a self-destructive junkie to unhinged super-baddie (and sometimes back again). Lenny, her character, is really around a dozen people at once. It’s hard to explain—this is a show often filmed impressionistically, as if from the inside of a fever dream, and we rarely know what is real and what is not—but Plaza inhabits each persona with such eye-bulging, id-fueled relish, that confusion becomes part of her allure. She’s a spectacular, living nightmare. And nightmares rarely make sense anyway.

In a nutshell: Lenny is a friend of David Haller (Dan Stevens), the titular mutant of Legion, who lived in a mental hospital along with Lenny at the start of season one. (In the comics, Legion is also the son of Professor X, leader of the X-Men, though the show takes place in a different continuity.) He’s a diagnosed schizophrenic, though we eventually learn he possesses incredible psychic superpowers. An explosive mishap at the hospital, however, accidentally phases Lenny through a wall, leaving her body mangled and her consciousness susceptible to a psychological parasite infecting David called the Shadow King. The King torments David in many forms but from then on, most often, it’s as Lenny.

His evil, all-consuming energy clashes with and remixes her junkie’s desperation, leaving Plaza to absolutely go nuts reimagining Lenny with every appearance. She plays Lenny in a man’s three-piece suit, masculine and menacing; Lenny in fishnet stockings and horn-rimmed glasses, chaotically seductive; Lenny in slicked-back hair and a leering grin, taunting David: “You killed me, man!”

“ You start to see her as just a frightened little girl. I think most villains start out that way. ” — Aubrey Plaza

However, in Tuesday night’s episode, “Chapter 13,” she plays Lenny in a way we haven’t seen: as vulnerable, confused, and genuine. She is human again, quite literally. The Shadow King has abandoned Lenny’s form in favor of a man named Oliver (Jemaine Clement), so she begs and bargains with him to create a new body for her and let her go. He does, but not for free. In the episode’s final minutes, we witness a horrific transformation: he effectively kills David’s sister, Amy, and turns her body into one just like Lenny’s, albeit with blue eyes. Being the King’s “hostage, violated like a puppet,” as she puts it, profoundly changes Lenny. “In a way, I’m a completely new character now,” Plaza says in a phone conversation ahead of her newly sympathetic turn. “You start to see her as just a frightened little girl. I think most villains start out that way.”

Lenny reunites with David in an interrogation room, where she begins to unravel details about her life before David. Her real name is Lenore, we learn, named after her alcoholic grandmother. (“She was a real salty broad and leave it at that,” Lenny says, her penchant for old-timey slang still in tact.) Her dad was an unemployed porn addict. She alludes to having a pimp. Her only romantic relationship, she reveals, lasted one week in high school: “If he was gonna jab something hard in me, I sure as shit was gonna return the favor.” No one, David least of all, cares to listen. Every good guy in the room is convinced she’s still under the Shadow King’s control.

“I think it was really kind of traumatic for me to experience that transition as Lenny,” Plaza says of her character’s fall from the height of lunacy in season one to the powerless wreck she is now. “You know, we don’t get the scripts in advance that much so I’m kind of flailing around on the astral plane trying to ground myself in something real, and you kind of never know what’s real and what’s not. It was a really different experience to go inward and find the vulnerable side of Lenny and let all the other stuff fall away.”

Plaza, 33, is known for her sardonic bite—or at least, for the caustic, deadpan quality she brought to the role of Parks & Recreation’s April Ludgate for seven years. (She is perfectly polite in our conversation.) She inhabited the role so effortlessly that, for a while, sullen misanthropes became kind of her thing: she did it in Scott Pilgrim vs. the World, in Funny People, and so on. (Her character in Whit Stillman’s Damsels in Distress was called Depressed Debbie. In Life After Beth, Plaza went full-tilt and just played dead, as a zombie.) Recently though, roles like the titular stalker in last year’s social-media satire Ingrid Goes West, a raunchy nun in The Little Hours, and Lenny have allowed Plaza to come fully alive—and unhinged.

Legion in particular, she says, is a challenge wildly unlike any other. Lenny’s shape-shifter quality (and showrunner Noah Hawley’s reliably last-minute scripts) require that she essentially play “multiple characters with one role, which I’ve never really gotten to do,” she says. “I feel that I’ve pushed that to the max in every different situation on the show. I’m always interested in coming up with a different look and a different version of Lenny because when you have something that is so open to interpretation and not grounded in reality, you can really let your imagination go. It’s just been a really fun exercise for me to try and tap into the emotional truth of the character but also having fun coming up with these different interpretations of her personality and who she is in each moment and what she wants.”

Hawley originally wrote Lenny as a 50-year-old man. Plaza delighted at the prospect, but imposed one condition: he could not change the dialogue to make Lenny more feminine, hence the character’s gender-bending, David Bowie-inspired mania. Plaza says she feels lucky now to have come across the “rare” part. “But it’s hard when you’re playing a character that isn’t even real,” she concedes with a laugh. “Lenny’s part of the story but she’s kind of on her own trip and I think the whole season I was trying to understand what that was.”

Parsing out Legion’s ever-twisting trip of a plot becomes extra difficult when you can’t bring yourself to watch the show. Plaza has yet to binge its second season, “but I will eventually,” she says. “I just kind of have a hard time watching anything that I’m in.” The season’s boldly weird visual flourishes, often not in the script, will come as a surprise when she does: “I just need distance from it I think because when I’m shooting it, I have such a clear idea what’s happening in my own imagination. So in some ways it’s always like a slight disappointment to see it because I’m like, oh, it was different in my head.”

Still, Plaza hopes to direct herself in an episode next year, and someday write and direct a feature of her own. She served as producer on Ingrid and The Little Hours, a role that “kind of opened my eyes to all the possibilities of being behind the camera and having an impact on projects creatively in a different way than just acting.” She’s had her eye on the director’s chair since film school at NYU, where she studied directing and writing. “So I’m really fired up about it,” she says.

In the last few months Plaza has also helped raise funds for Puerto Rico, where her dad’s family hails from, in the aftermath of Hurricane Maria. The Trump administration’s sluggish response to the humanitarian crisis—swaths of the island went without power for months, and a full blackout hit again in April—angers Plaza. “I think it’s completely ridiculous,” she says. “I think if those things had happened on the mainland or in a different place, it would have been different. So it’s really hard to watch. It’s really upsetting.” She has cousins there, one of whom (hi, Hector) she messages on Instagram to keep in touch with. “I’m trying to figure out a way to go over there at some point,” Plaza says. “But thank god all my family’s OK.”

In the meantime, there is Lenny, whom Plaza has reinvented one more time. “I’m not a villain,” she screams at David at one point in “Chapter 13.” She’s also not just Lenny anymore. While she and David fall into old, familiar patterns while conversing, holdovers from their days as best buddies, Lenny now has “half the DNA” of his poor sister in her body—and likely another voice in her head. “It’s a really confusing time for her,” Plaza laughs.

For her and us all.