All 10 The Big Bang Theory Returns & Cameos In Stuart Fails To Save The Universe
Stuart Fails to Save the Universe is the most ambitious spinoff of The Big Bang Theory to date. The cast of Stuart Fails features comic book store owner Stuart Bloom (Kevin Sussman), his girlfriend Denise (Lauren Lapkus), and Caltech scientists Bert Kibbler (Brian Posehn) and Barry Kripke (John Ross Bowie), who are unexpectedly tasked with saving not just their world, but every world.
Stuart Fails to Save the Universe is the boldest Big Bang Theory spinoff in so many ways. It’s the first not to be a prequel, the first to have a shorter season to stream on HBO Max instead of a longer season to air on CBS, and the first to embrace true sci-fi elements.
Set after the events of The Big Bang Theory, it promoted characters fans already knew to be the stars of the show. It also had the opportunity for fun cameos from the main cast of The Big Bang Theory to show up and play a version of their character for an episode. From the very first episode of Stuart Fails to Save the Universe, fans were surprised by a major cameo from one of the original main characters. Almost every episode took place in a new universe and had a guest appearance from a TBBT character.
While trying to mesh the multi-cam humor of The Big Bang Theory with the high-concept sci-fi premise didn’t work perfectly for audiences or critics, the show has the chance to work out the kinks in Stuart Fails to Save the Universe season 2, which HBO Max renewed well before the first season was even over. Surely there are more cameos to come in season 2!
Raj Koothrappali - Dystopian Prisoner
Episode 1, “Spoiler: Gary Dies”
Kunal Nayyar’s Raj appears in the very first episode of Stuart Fails, immediately establishing how much this world has forced the familiar characters to change. It’s funny but unsettling to see Raj so completely unhinged by his fear of warlord Kripke that he initially believes Stuart, Bert, and Denise are hallucinations.
Raj's eventual death gives the episode real stakes, even if the show ultimately undercuts them by establishing that there are infinite versions of every character. Raj’s beard and increasingly wild ideas also signal that this is a very different version from the sweet, romantic character audiences knew on The Big Bang Theory.
When Raj is revealed in captivity, the dramatic push-in turns the moment into a genuine hero shot, making his brief appearance feel surprisingly triumphant. Nayyar’s cameo was also kept remarkably secret, allowing his sudden appearance to be a genuine surprise for fans.
Penny & Zack - Rebel Resistance Leaders
Episode 2, “Spoiler: Zack's in This One”
In a world where AI forces everyone to be kind under threat of punishment, Penny (Kaley Cuoco) becomes a rebel resistance leader. It’s fun to see her tough, in control, and physically capable, a far cry from the young, insecure girl from Nebraska audiences met at the beginning of The Big Bang Theory.
Penny “deprograms” Stuart, Bert, and Kripke through physical violence, repeatedly smacking them across the face, and the show makes a meal out of the absurdity. Zack (Brian Thomas Smith) is also part of the resistance, and this version of him seems far more capable than the lovable but clueless character fans knew on TBBT.
At the end of Stuart Fails episode 2, the group abandons Penny, Zack, and the dystopian universe. After the first episode, it wasn’t clear if seeing Raj was a fun one-off, but this episode made it clear fans should expect to see more familiar faces in unexpected places.
Ramona Nowitzki - Caltech Front Desk
Episodes 2 & 7, “Spoiler: Zack's in This One” & “Spoiler: Dexys Midnight Runners Get a Royalty Payment”
Ramona Nowitzki (Riki Lindhome) was a minor character on The Big Bang Theory, a physics graduate student who works for Sheldon (Jim Parsons) and prioritizes his research at the expense of everything else in his life. In Stuart Fails to Save the Universe, she returns in two episodes, as a Caltech front desk assistant, making for a fun pair of cameos for TBBT fans.
In episode 2, AI forces everyone to be friendly. Nowitzki uses malicious compliance to be as unhelpful as possible while maintaining a relentlessly chipper expression, knowing that overt rudeness could get her electrocuted.
Then, in Stuart Fails episode 7, when everyone can telepathically hear one another’s thoughts, she doesn’t bother disguising her frustration and bitterness about her job and life. Both appearances put a hilarious new spin on her familiar intensity.
Bernadette Rostenkowski - Witch-Demon
Episode 3, “Spoiler: Bert Is Magic”
In Stuart Fails episode 3, Stuart and the gang find themselves in a world filled with magic, where Bernadette (Melissa Rauch) is known as a powerful sorceress. When they visit her for help, she claims the WGA (Wizards’ Guild of America) took away her magic and says she only needs the blood of an innocent to reverse the binding and help them.
Of course, Bernadette isn’t quite what she seems. She’s actually a power-obsessed demon who transforms into a gigantic, scaled creature in her true form. It’s a funny take on Bernadette, whose diminutive stature on The Big Bang Theory often contrasted with her domineering personality.
Despite being one of the smallest members of the group, Bernadette could be surprisingly harsh, manipulative, and even downright scary when she wanted something. Turning those qualities into a literal witch-demon feels like a particularly fitting alternate-universe twist on her character.
Amy Farrah Fowler - Psychiatrist
Episode 4, “Spoiler: Stuart Makes a Wallet”
Stuart Fails to Save the Universe gets increasingly meta in episode 4, when Stuart finds himself in a psychiatric hospital with The Big Bang Theory's Amy Farrah Fowler (Mayim Bialik) as his psychiatrist. He explains that, in his original universe, Amy was a neurobiologist, to which she responds with the dry quip, “Good for me,” a joke that works on multiple levels given Bialik’s own advanced degrees in neuroscience.
This version is noticeably more jaded and less quirky than the Amy fans remember from The Big Bang Theory. Rather than the socially awkward scientist who is tied to one man’s neuroses, this Amy is a professional tasked with helping anyone who needs it.
It’s a small but clever twist that lets Bialik play a familiar version of Amy while still making her feel distinct. It felt like there might be something nefarious about Amy herself, since the psychiatric hospital is a construct to make Stuart not believe in his destiny, but she is a benign part of this particular universe.
Raj Koothrappali - Doomsday Truthteller
Episode 6, “Spoiler: Corn Is Delicious”
Stuart and Denise decide to make the most of it and settle down in a world where humans are herbivores who chew their cud in Stuart Fails to Save the Universe episode 6. While there, they randomly encounter Raj on a street corner screaming at anyone who will listen that entire star systems are disappearing, and the end is nigh.
His warnings don’t have much of an effect on Stuart, but it’s a great use of Raj’s expertise as an astronomer. Rather than simply dropping another The Big Bang Theory character into an alternate reality, the episode uses Raj’s scientific knowledge to organically raise the stakes and hint at the larger threat facing the multiverse.
It’s also a funny contrast to Raj’s earlier appearance, where his paranoia made him question reality itself. Here, though, he seems crazy, he may actually be the one person who understands what’s happening.
Bernadette Rostenkowski - Children’s Tap Dance Instructor
Episode 7, “Spoiler: Dexys Midnight Runners Get a Royalty Payment”
Trying to find The Big Bang Theory's Howard Wolowitz (Simon Helberg) in a universe where everyone can hear each other’s thoughts, Stuart and the gang instead encounter Bernadette. She’s just as acerbic and mean as the original Bernadette, but this version of her is even more miserable, stuck working as a children’s tap dance instructor despite openly hating the job and the little girls she teaches.
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The cameo plays into Bernadette’s sharper personality, but there’s an amusingly bleak twist: She’s married to someone who isn’t Howard, yet still manages to hate her husband just as much. After seeing so many alternate versions of The Big Bang Theory characters suffer, it would be nice to get a universe where Bernadette is genuinely happy and fulfilled.
Penny - Army Major
Episode 8, “Spoiler: We're as Confused as You Are”
The gang find themselves court-martialed in Stuart Fails to Save the Universe episode 8, with "Firing Squad" Penny appearing as the ruthless Army Major arguing for the prosecution. It’s similar to the previous alternate version of Penny: she’s still tough, commanding, and more than willing to use violence, but this time she’s working for the government rather than fighting against it.
Unfortunately, Penny’s cameo takes an especially bizarre turn when she becomes trapped in the centaur universe. The visual is certainly funny, as a horse on the bottom but still in army dress uniform up top, but it doesn’t feel like the best use of the character. It would be interesting to see a version of Penny who succeeded at her original dream of becoming an actress.
Amy Farrah Fowler - The Flash’s Girlfriend
Episode 9, “Spoiler: We Couldn't Get Green Lantern”
Trying to find The Flash in Stuart Fails episode 9, Stuart and the gang instead stumble upon Amy Farrah Fowler. She seems to be much closer to her usual self in this universe, although the episode never makes clear what she does for a living. The major difference is her relationship status: Amy is now dating Jay Garrick (Andy Ridings), aka The Flash.
The cameo is somewhat undercut by the fact that she is sharing screen time with Jay, who is hardly a major DC superhero. The episode’s title itself is a joke about the fact that the production couldn’t afford Green Lantern.
Poor Amy can’t seem to catch a break in any universe. On The Big Bang Theory, Sheldon’s famously limited interest in sex meant he (usually) only had coitus on Amy’s birthday. Here, things aren’t much better: Jay is apparently finished in the boudoir before Amy even realizes what’s happening. It’s another funny, surprisingly bleak twist on her love life.
Ramona Nowitzki - Gotham Airline Flight Attendant
Episode 9, “Spoiler: We Couldn't Get Green Lantern
Sheldon’s biggest fan returns briefly as a disaffected flight attendant for Gotham Airlines in Stuart Fails to Save the Universe episode 9. By this point, the series has become increasingly convoluted, quite literally taking Stuart and the gang inside a comic book, but it still finds ways to reward The Big Bang Theory fans with familiar faces in unexpected roles.
Ramona Nowitzki’s appearance is little more than an Easter egg, but casting the small part with a recognizable face makes the alternate universe feel more connected to the original series. Her brief appearance also provides another amusing twist on Ramona, who was previously seen as a Caltech receptionist earlier in the season.
Rather than the obsessive graduate student who once pursued Sheldon, this version is simply another weary employee, dealing with Gotham travel disasters and airport sushi. It’s a blink-and-you’ll-miss-it cameo in Stuart Fails to Save the Universe, but longtime fans will appreciate the callback.
- Release Date
- July 23, 2026
- Network
- HBO Max
- Directors
- Kyle Newacheck
- Writers
- Bill Prady, Chuck Lorre, Zak Penn
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