"What If... Zombies!?" is the fifth episode of Marvel's Disney+ series What If...?. It premiered on September 8, 2021. It was written by Matthew Chauncey and directed by Bryan Andrews. This episode is based on Avengers: Infinity War.
When the Avengers are infected by a zombie plague, the surviving heroes search for a cure.
Bruce Banner crashes into the New York Sanctum just like in Infinity War, but this time Strange and Wong are not there. Instead, the Cloak of Levitation hides just out of his sight. Finding appropiate clothing to change into, Banner heads outside to finds the outside silent and empty of life. Wondering if he was too late, Banner watches as Ebony Maw and Cull Obsidian appear down the street, making their announcement to the empty street is. However, Maw is surprised by a repulsor blast to the back of his head from Iron Man's gauntlet via a mystic portal. A portal opens with the silhouettes of Iron Man, Wong and Strange exiting. Stark's blasts cause a dust cloud, obscuring a vicious overkill battle against the two; in which Maw and Cull are killed. Banner is shocked until Stark faces him, revealing a damaged snarling face. They are all zombies, and to make things worse, Cull and Maw also have turned.
Banner quickly begins running away, but is topped by Maw's telekinesis stops him. Right before Stark can get to him, the Cloak of Levitation tosses Iron Man away, allowing Banner to flee. Wong attempts to follow him through a portal, but the cloak stops him and the same this that it also restrains Strange's arms. The closing portal decapitates Wong, but the other three zombies approach Banner after Maw paralized him. Luckily, Hope van Dyne arrives and uses her control over insects to attack the zombies, reducing Strange, Maw and Cull to bone. Seeing Stark's armor protected him from the attack, Hope orders Banner to flee with her giant ants. When he protests, Spider-Man picks him up instead. Hope uses a blast to knock Stark's head off, neutralizing him. While web-swinging away, Spidey introduces himself as "friendly neighborhood" Spider-Man to the rattled Avenger. This prompts Banner to ask what happened to the neighborhood.
- “Like too many great catastrophes in history, this one sprang from a place of love and hope. Two weeks earlier, Dr. Hank Pym journeyed into the Quantum Realm searching for his long lost wife. But in this universe, Janet van Dyne contracted a quantum virus that corrupted her brain. So when she reunited with her husband after 30 long years, oof! That happened. Alas, Hope van Dyne's long awaited family reunion was not to be. Within 24 hours, the entire Pacific Northwest was infected. Ironically it was the Avengers' heroism that sealed humanity's fate. Because once Earth's Mightiest Heroes joined the infected, no-one else stood a chance. Unless, of course, they knew the rules.”
- ―The Watcher
In this version of reality, when Hank finds Janet in the Quantum Realm, she unmasks to reveal a hideous snarling face as a result of a quantum virus that corrupted her brain. To Hank's horror, Janet quickly pounces on him, breaking his helmet and infecting him. They somehow pilot the ship out of the quantum realm and back to Hank's lab. When Hope checks on the fogged up door, Hank attacks; luckily she shrank and flew away. Scott Lang wasn't as lucky; Janet got him. It only got worse from there, the three zombies then began infecting everyone they came across; within a day, a huge chunk of the Pacific was turned. By that point, the Avengers (Hawkeye, Captain America, Black Widow, Iron Man and Black Panther) arrive on the Golden Gate Bridge to fight the zombies. However, before they can do anything a shrunken Hank bites Cap's neck and returns to normal size, pinning him down. The Avengers begin fighting them off; Iron Man uses his repulsor blasts, Black Widow and Hawkeye fire their weapons on the zombies, Black Panther fights hand-to-hand. However, they are all along quickly overwhelmed and are knocked down by the zombies
In the present time, Spider-Man made survival video working with Happy Hogan, Bucky Barnes and Sharon Carter. The video shows steps on how to survive the zombie apocalypse. The first step is expose as little skin as possible to avoid bites. The second step is bath frequently, because the less pheromones given off, the less chance zombies will be attracted. The third step is always aim for the zombie's head. Spidey is showing the video to Banner who is along with the Cloak at his group's base, which is composed of school buses that are suspended between buildings with his webbing for their safety. Okoye reveals that another survivor came claims to have a cure for the zombie problem; the message comes from a S.H.I.E.L.D. base in New Jersey. Sharon agrees the base would have the equipment needed for such a task.
Using the shrinking cars, the group safely gets to Grand Central station. Okoye orders Hope, Kurt Peter and Banner to track seven to get a train working while the others to stay guarding the place. Peter asks if Wakanda doesn't have horror movies, because splitting up the group often gets people killed in them. Regardless, they start working on the train. In the lobby, Okoye and Bucky patrol. While Sharon and Happy are on patrol, Happy gets struck by an arrow and dragged off, despite using a repulsor glove to fire at his assailant. It's a zombie Hawkeye. Joined by a now-zombified Happy, they attack Sharon. She manages to kill Happy with his own weapon and steals it before escaping. To make matters worse, a zombie Falcon breaks into the lobby; but they kill it. At the tracks, Peter is nearly killed by zombies while helping unstuck the train; however, the Cloak rescues him and chooses Peter as its next owner. It crashes him into the train with everyone onboard. Okoye apologizes to Peter for making them split up, realizing he was right when he suggested against it earlier.
Their reprieve on the train doesn't last long. While keeping guard in the last car, Sharon hears something land on the train. It crashes through as the train enters a tunnel. Bucky hears her scream as shots are fired. He gets to the last car, where he finds zombie Captain America having killed Sharon. As Bucky fights Cap, who he punches with his metal arm to deflect his shield and keep safe from bites. During this, a zombified Sharon gets up and tries attacking; Bucky tosses her in the back as Hope arrives to deal with her. Using Cap's shield, Bucky bisects the zombie, making him fall out of the train. Hope flies into Sharon's mouth and explodes her from the inside, only for everyone else to arrive and see she got wounded in the fight, so she's doomed. The Watcher's silhouette watches the train.
Later, Bruce notes Hope's health is deteriorating. Hope wishes to be killed for their safety; Okoye is against it as there may be a cure. Peter, however, is hopeful about the cure, making Hope ask how he can be. Peter tells her that he keeps going because its what those who they lost would want them to do. To make matters worse, they are out of fuel and surrounded by zombies. However, the base is just through the sea of undead, so Hope offers to sacrifice herself to ensure that the rest of the group arrives there safely. She turns into Giant-Woman, carrying everyone and squishing zombies along the way. She safely puts them behind the fence of the base as zombies crawl up to her helmet and begin punching the glass. She shakes them off and falls over, dying in peace.
Bucky wonders why the zombies aren't climbing the fence. Peter tells him that they don't need to, noticing that the fence is broken. Kurt says that he can feel the witch Baba Yaga. They are then surprised by the Vision, whom Banner hugs in joy; being an android had the perk of keeping him safe. Vision explains the Mind Stone emits a low level frequency unpleasant to the infected. His research shows that the quantum virus overloads the limbic system. His experiments in targeted exposure reversed the infection on Scott Lang, but he's just a head in a life preservation jar now. Scott tells bad jokes to deal with his trauma. Vision explains that theoretically he can cure others. However, as Banner and Peter think of broadcasting the signal worldwide, Vision reveals that the technology is beyond human capability. Okoye reveals Wakanda does and its been protected the entire time by the forcefield. Bucky goes to look for transport, only for Vision say he won't find what he's looking for.
Banner finds out from the logs that they weren't the only survivors to arrive; Peter wonders where they are, making Vision give a dark look unbeknownst to them. Bucky investigates the base, finding it empty except for a pile of lab coats. Hearing a zombie rasping, he shoots at the source, only for his shot to hit bullet proof glass; behind which a zombified Scarlet Witch rise and stares at him. As Bucky discovers that Vision is keeping zombie Wanda around, he soon hears a weak voice calling out; he rushes nearby to find T'Challa, who is missing a leg. T'Challa warns that they must leave. Bucky helps him limp back to the group, unknowing of the fact that Scarlet Witch has begun working her magic on the fracture in the glass keeping her secure.
Vision tells Banner that he wished he hasn't found that log. Bucky enters with T'Challa, whom reveals Vision saved him in San Francisco to serve as food for his zombified bride. Vision states that his actions, while unsavoury are all logical. To Vision's own sorrow, Wanda resists the Mind Stone treatment because her powers are too strong; unable to eliminate her out of love, Vision settled for containing her. Okoye goes to stab him, only for the room to rumble. Vision states that they have woken her and Wanda hasn't eaten in days. The door break down with a red glow as Kurt is pulled away by a hungry Wanda, screaming "Baba Yaga". The Cloak saves Scott, whose jar was about to fall over; working for him. Banner asks Vision to get them out as Parker webs up Wanda. Seeing the Wanda he knew is no more, Vision blasts a hole to the surface, which everyone escapes through. However, Okoye is pulled back in by Wanda. Vision destroys the ground above the room, crushing both of them.
Repentant, Vision points them to a jet they can use to get to Wakanda, pulling out the Mind Stone and ending his life. Unfortunately, Wanda survived and gets back to the surface. Turns out a part of Wanda recognizes Vision as she examines his lifeless body. While kneeling by him, Wanda repels Bucky's bullets as Peter, Banner, Scott and T'Challa head to the jet. A seemingly grieving Wanda sends Bucky flying into the crowd of zombies. Worse, it turns out the Mind Stone's repelling field only worked when Vision's consciousness controlled it; so the zombies go after the survivors again. Banner sacrifices himself to distract the zombies. Hulk finally comes out and faces off against Wanda, allowing the jet to take off. However, a zombified Hope gets up and tries holding the jet, but they burn her face with extra thrust. Futilely, she tosses a zombie at them, who gets off a comical "ouch" before falling off from the wing of the jet.
The next day, Peter finally lets out his grief; he's lost everyone he's ever loved. T'Challa tells him that in Wakandan traditions, it is believed our loved ones stay with them so long as they are remembered. As they head Wakanda, the screen heads way before them, showing that Wakanda had been infected during their absence. And more horrifying and bizarre is that a zombified Thanos is standing there with the other five Infinity Stones. The undead tyrant smiles.
- “Even in the darkest of times, humans will give all to save their planet. Even if it might bring an end to the universe....”
- ―The Watcher
- Jeffrey Wright as The Watcher
- Mark Ruffalo as Bruce Banner/Hulk
- Chadwick Boseman as T'Challa/Black Panther
- Paul Bettany as Vision
- Sebastian Stan as Bucky Barnes
- Evangeline Lilly as Hope van Dyne/Wasp
- Paul Rudd as Scott Lang/Ant-Man
- Jon Favreau as Happy Hogan/Zombie Happy
- Danai Gurira as Okoye
- Emily VanCamp as Sharon Carter
- David Dastmalchian as Kurt
- Hudson Thames as Peter Parker/Spider-Man
- Tom Vaughan-Lawlor as Ebony Maw
- Josh Keaton as Steve Rogers/Captain America
- Ashley Adler as Additional Voices
- Piotr Michael as Additional Voices
- Fred Tatasciore as Additional Voices
- Michael Ralph as Additional Voices
- Robin Atkin Downes as Additional Voices
- Matthew Wood as Additional Voices
- Matt Yang King Additional Voices
- Mike Vaughn as Additional Voices
- Terri Douglas as Additional Voices
- Debra Wilson as Additional Voices
- Kari Wahlgren as Additional Voices
- Ashley Peldon as Additional Voices
- Dave Boat as Additional Voices
- This episode is based on the comic run Marvel Zombies by Robert Kirkman and Sean Phillips.
- This episode is based on Avengers: Infinity War, which includes Banner falling into the Doctor Strange's home in New York.
- Kevin Smith makes a non-speaking cameo as one of the zombies.
- This is the second time Danai Gurira plays a heroine fighting off a zombie apocalypse, the first being her role as Michonne in The Walking Dead.
- Spider-Man mentions his parents and Uncle Ben for the first time in the MCU. Peter also implies that Aunt May died as he says "Aunt May used to say..." before briefly stopping.
- The Avengers team that went to San Francisco consist of Pro (Iron Man, Black Widow, Black Panther) and Anti (Captain America and Hawkeye) Accords factions, which at this point were still separated in the main timeline after they fought each other during the events of Captain America: Civil War.
- This is the second episode out of the 4 in which Chadwick Boseman voiced T'Challa before his death.
- Characters such as Wong, Iron Man, Doctor Strange, Falcon and Black Widow appear, but do not have speaking roles as they are infected by the zombie plague.
- Despite having no consciousness, the infected retain the ability to use their skills, weapons and powers.
- Vision reveals he was able to heal Scott Lang using the Mind Stone, because its power can neutralize the virus which infects the brain's limbic system of the individual. The limbic system is the region of the brain responsible for controlling emotion, behavior and memory; a dysfunction in it is associated with disorders that affect personality and behavior, such as schizophrenia, autism, epilepsy, limbic encephalitis, dementia, and anxiety disorder.
- According to Vision, Wanda's infection cannot be treated because her powers are so strong that she resists the Mind Stone. This happens despite her powers coming from the Mind Stone and she also having a piece of the stone inside her as seen in WandaVision.
- It's not explained how Thanos ended up zombified in Wakanda at the end.
- Hulk refuses to come out of Banner like in Infinity War, but he does eventually come out, unlike in the movie, where Hulk doesn't come out of Banner at all after his fight with Thanos. Additionally, it turns out his "Hulked out" skin can't be bitten by zombies.
- Hope van Dyne grows to giant size for the first time in the MCU.
- It's confirmed by the Watcher's narration in the beginning of the episode that Ant-Man and the Wasp happened two weeks before Infinity War.
- The movie rights to Spider-Man still being negotiated between Disney and Sony is the reason why Tom Holland doesn't voice Spider-Man.
- Despite being active at the time of the zombie apocalypse, this episode doesn't feature Yelena Belova, Melina Vostokoff, Red Guardian, Shang-Chi or any of the Eternals, since Phase 4 will be covered in Season 2.
- Banner says "You guys are screwed", a line similar to the one he says in Infinity War when Thor appears in Wakanda.
- Spider-Man's suit is based on the one used at Disney parks instead of the one used in Infinity War.
- Zombie Wong is killed the same way he sliced off Ebony Maw's arm in Infinity War.
- When Zombie Janet van Dyne attacks Scott, his hand goes across the glass in a classic horror fashion.
- Steve is seen in his suit from Captain America: Civil War.
- Happy Hogan's information on being a boxer is a reference to his past as a boxer in the comics and when he trained Tony Stark in Iron Man 2.
- Happy wears Tony's wrist watch repolser from Captain America: Civil War.
- Bucky's information mentions deep sleeper, referencing that he went under the ice until he was needed to used as the Winter Soldier.
- Camp Leigh is seen, the location in which Steve Rogers trained in the First Avenger.
- Bucky tells Cap, "Guess this is the end of the line" after destroying zombie Cap, referencing their lines "I'm with you 'till the end of the line" from Captain America: The First Avenger and Captain America: The Winter Soldier.
- Zombie Cap throws his shield at Bucky, who catches, just like how he catches it in Captain America: The Winter Soldier, and darker version of Captain America's theme is played during this scene.
- The bunker that everyone finds Vision in is similar to the one that Steve and Natasha visited in the Winter Soldier and found an AI version of Arlim Zola.
- When Scott is saved by the Cloak of Levitation, he says "Wingardium Leviosa", a spell from the Harry Potter franchise.
- Vision pulls out the Mind Stone from his head, like Thanos pulled it from him in Infinity War. This is the fourth time Vision has died in the MCU.
- Banner tells Peter to avenge the other heroes, promoting him to an official Avenger, just like when Tony Stark knighted Peter and made him an official Avenger in Infinity War.
- T'Challa tells Peter, "In my culture, death is not the end", which is a callback to Captain America: Civil War, when T'Challa says the same after T'Chaka's death.
- Okoye tells Hope that Peter has hand sanitizer, which could be referencing the ongoing Coronavirus pandemic, which was also happening when this episode was recorded.