The Big Bang Theory Season 12, Episode 6 Recap: Those Epic Halloween Costumes Explained

The Big Bang Theory didn't just go big for its final Halloween episode of the series—it went epic, from a Supreme Court justice to an eighties cartoon character. The writers, actors, and costume department pulled out all the stops to propel the story forward while paying homage to its iconic characters. Every costume was made in-house in a matter of weeks; no easy feat when you're talking about the Bill of Rights or a helicopter propeller. And the episode's main story—Sheldon getting his feelings hurt when Howard dressed up as him for Halloween—was actually loosely based on a real-life event that happened to one of the writers. Given all the heavy lifting that went in to creating the episode, executive producer and showrunner Steve Holland gave Glamour.com the exclusive details on how it all came together.

This episode was inspired by a real-life event. One of the series' writers, Erik Kaplan, previously worked on Malcolm in the Middle, and one Halloween another writer dressed up as him. "I don't think his feelings were hurt like Sheldon's," Holland says. "But it was such a great jumping-off point for a funny story that had real emotional repercussions for the characters. The thought of getting to see Simon Helberg do his Sheldon impression seemed really exciting, and that led to the idea that Sheldon and Amy could get their revenge by dressing as Howard and Bernadette. The whole thing really started to take shape."

Every costume in "The Imitation Perturbation" was custom made. Mary T. Quigley is Big Bang's costume designer; she and her team spent weeks creating each Halloween costume. "Working Inspector Gadget and U.S. Constitution costumes aren't exactly things you can get off the shelf," Holland says. "She did a ton of research, and we actually had long discussions about the Bill of Rights on the back of the Constitution costume. She had gone to the National Archives website to find what that looked like." In fact there were a lot of conversations about that image and whether it was the proposed amendments or the ratified amendments. "That's the level of attention—and pure nerdery—that went into everything."

There's a secret meaning behind Raj's Kooth Bader Ginsburg costume. Perhaps one of the most timely costumes this season is Supreme Court Justice Ruth Bader Ginsburg, who is the subject of her own documentary as well as an upcoming movie starring Felicity Jones. But Big Bang writers took it a step further and had Raj go by Kooth (from his last name, Koothrappali) Bader Ginsburg as a fun play on words. "It seemed very in character [for him]" Holland says. "Kooth Bader Ginsburg made us laugh." The only thing the writers couldn't decide on was whether to give Raj a bun or not. "In the end, since he was 'Kooth' Bader Ginsburg, we decided that he could go without a bun." As for why the writers also wanted Raj's new fiancé, Anu, to go as the Bill of Rights, Holland says they wanted them to have a couples costume to show that their relationship was progressing and they were getting more comfortable with each other.

This surprising costume was the most time-consuming of all. From the outside looking in, Sheldon Cooper is a simple man. His daily wardrobe never veers far from a T-shirt over a long-sleeve thermal. So what could be that hard about dressing up as Sheldon? Turns out quite a bit. Holland says that having Simon Helberg dress up as Sheldon was the most time-consuming of all the costumes because of Sheldon's matted, perfectly coiffed hair. "Simon had a blast dressed up as Sheldon, but he spent hours in the makeup chair because it was extremely time-consuming hiding his real hair under a bald cap and then laying Sheldon hair on top of it." And while Simon had easy access to Jim Parsons in case he needed any tips on how to play Sheldon, none was needed. "Simon is actually a really terrific impressionist," Holland says. "I love that his choice was not to do a straight mimic of Sheldon, but to exaggerate him to a caricature."

Here's why Howard and Bernadette dressed up as Mary Poppins and Bert. "Howard and Bernadette are really playful together, so we wanted them to have something with a sense of whimsy and fun attached to it," Holland says. "We wanted something that seemed appropriate for the characters and not random. And it seemed like Howard would love getting to do his best cockney—or worst cockney, as the case may be—accent."

And why Sheldon and Amy were Doc Brown and Clara from Back to the Future III. Holland and the writing staff are huge fans of Back to the Future. (Hey, Michael J. Fox, now's the time for a cameo!) But by coincidence, Holland and fellow executive producer Steve Molaro got to have lunch with Back to the Future director Robert Zemeckis after they wrote the script for this episode. "I tried not to gush," Holland says, "but I was very excited to tell him that we were using Back to the Future in our Halloween episode."

Why dressing up as Inspector Gadget wasn't as easy as it looked. The wardrobe department created the elaborate propeller Leonard wore to play Inspector Gadget, but according to Holland, it was "heavy and awkward." The blades were originally much longer, but it was "hard to walk around the set without hitting people," Holland says. The propeller was also hard to balance, so the wardrobe team had to keep cutting the blades down until they found a length that worked.

The reason Penny didn't play Inspector Gadget's niece, Penny. Die-hard I.G. fans know that Penny secretly does all of her uncle's work during his missions, even though he (groan) takes all the credit for it after. So why didn't Big Bang's Penny play her, which could have led to some interesting back and forth? "It's funny, Johnny Galecki texted me when he got the script to ask why she wasn't dressing as Penny from Inspector Gadget since they even share a name," Holland says. "The truth is, when we were first writing it, she was Penny from Inspector Gadget, but since Penny is Inspector Gadget's niece and Leonard and Penny were talking all about their first kiss, it started to cast a weird tone over the scene. So we changed it." Good call.

The costume of all costumes: Mayim Bialik as Bernadette and Jim Parsons as Howard. I don't know about you guys, but I could have watched an entire episode of Amy as Bernadette and Sheldon as Howard. Holland agrees. "Mayim looked so good as Bernadette! She actually had a really bad cold earlier in the week and was worried she wasn't going to be able to get her voice up high enough to do Bernadette. Luckily she recovered over the weekend and was hilarious."