'American Horror Story' reveal stuns viewers, but Chloe Sevigny warns, 'It gets even creepier'

Sarah D. Bunting
Yahoo! TV
Chloe Sevigny as Shelley in "American Horror Story: Asylum"

WARNING: The following article may contain plot and casting spoilers for "American Horror Story: Asylum." If you don't want to know what happens, stop reading now!

Everyone had a tough time in the most recent episode of "American Horror Story: Asylum." Kit and Grace's latest escape attempt failed, Sister Jude fell off the wagon, and Sister Mary Eunice is probably possessed.

But nobody had it worse in "Nor'easter" than Shelley, played by Chloe Sevigny. Shelley bungled her own part of the escape plan, Dr. Arden tried to assault her, and when she interrupted the attempted rape by giggling at the size of Arden's, er, "stethoscope," he paid her back by amputating both her legs.

"AHS" fans know to expect "yikes!" moments like that -- but Twitter exploded after the big reveal, with everything from praise (CeeMarieGee: "AHS needs more of that kind of stuff. Yeah.") to lessons learned (TheNamesJB: "Moral of today's #AHS: Don't make fun of a man's junk size or you will lose your legs") to comments on the season as a whole (JasmineHull: "He cut off her legs? This season is beat"). One user, mabkkg, went so far as to find Arden's manners lacking: "He cut off her legs? RUDE!"

Chloe Sevigny, who plays Shelley, is no stranger to dark material, from her screen debut in Larry Clark's downbeat "Kids" to "Boys Don't Cry" and "Zodiac" -- but this is pretty extreme even for her résumé. Sevigny told Yahoo! TV that she'd read the first three scripts, and knew "from the get-go" that a double amputation was her character's fate. "At first I was kind of disappointed, because I wanted to be on the show more," she said, adding that she figured things "could only get worse" for Shelley from there.

Acting in prostheses is "a process," Sevigny said: she couldn't walk or stand on her own; she had to keep her legs bent, so as not to ruin the makeup that "creates" the stumps, and was pushed around set in a wheelchair; the makeup itself took three to four hours to put on, and took "a lot of patience, and gluing, and painting." But she immersed herself in the experience, with the help of the special-effects and CGI coordinators on set, learning to "sell it to camera. More than acting, it was more technical kind of stuff, you know -- do I move [the stumps] back and forth or up and down, how do they look the creepiest, which is what we're all kind of going for."

Sevigny's "not a Twitter person," so she didn't see the audience's collective "aaaaack" online last night, but she's "excited for people to see where it goes." Sevigny's only set to appear in three more episodes this season, and she's prohibited from getting into specifics about what awaits her character -- but she assured us that "it gets even creepier" for Shelley, and each appearance "is more shocking than the last."

More shocking than "Nor'easter"? We can't imagine what that means – and we're not sure we want to -- but Sevigny left us with one final hint: "She goes through… a transformation."

Watch a preview of "Nor'easter" right here:

'American Horror Story: Asylum' airs Wednesdays at 10 PM on FX.