WARNING: The following contains spoilers for What If...? Season 1, Episode 5, "What If... Zombies!?," streaming now on Disney+.
The world of the Marvel Cinematic Universe has been reduced to a zombie apocalypse in Episode 5 of What If...?, and it's up to a ragtag group of survivors to find a cure. After the virus was brought back from the Quantum Realm by Hank Pym and Janet Van Dyne, it spread rapidly, infecting a large number of the Earth's population (including a number of the Avengers). Hank and Janet's daughter Hope leads the survivors in their hunt for a cure, using the size-changing Wasp suit developed for her by her father.
Wasp and her crew (consisting of Bruce Banner, Spider-Man, Kurt, Sharon Carter, Bucky Barnes, Happy Hogan and Okoye) must travel to Camp Lehigh in New Jersey in search of a cure that has supposedly been developed there. After fighting off zombified versions of Earth's Mightiest Heroes, including Iron Man, Hawkeye, Captain America and more, the survivors board a train at Grand Central Station that will take them to their supposed safe haven. Unfortunately, the train runs out of fuel a short distance from Camp Lehigh, leaving them stranded and surrounded by zombies.
With no other clear option in sight as time runs out, Hope decides to make the ultimate sacrifice to help her friends escape. Taking a page out of Scott Lang's book, Hope grows to a giant size and carries her friends through the hordes of zombies, depositing them safely within the bounds of Camp Lehigh. She is then overwhelmed and collapses, with the infected swarming her giant corpse.
While Hope's growth spurt serves as a call-back to Scott Lang's transformations into Giant-Man in some previous MCU installments, it also references the Marvel Adventures series. In these comics, which are primarily geared towards young adults, Janet Van Dyne serves as a member of the Avengers under the name Giant-Girl. Instead of shrinking into the Wasp, that continuity's Janet can grow up to sixty feet tall. While the Wasp has shown the ability to grow in previous comics, this version of the character uses it as her primary ability, and What If...? marks the first time she has done it in the Marvel Cinematic Universe.
Unfortunately for What If...?'s heroes, Hope's sacrifice comes back to haunt them at the worst possible time. As the survivors (now joined by T'Challa) are attempting to escape to Wakanda onboard a Quadjet, a now-zombified and still giant-sized Hope rises and grabs the tail of their plane. Luckily, T'Challa is able to activate the jet's thrusters, pulling them out of her grasp and to safety. The zombified Wasp makes one final attempt to stop the survivors by throwing a zombie at their ship, but the poor creature just bounces off of it.
While Hope's sacrifice is incredibly noble and did allow her allies to make it to temporary safety, it may ultimately spell disaster for them. The episode's final moments reveal that a zombified Thanos is waiting for the heroes in Wakanda, with all of the Infinity Stones except the Mind Stone... which is in the surviving heroes' possession. In addition, the fact that there is now a giant-sized zombie walking around is sure to pose a challenge for any remaining survivors. Between the undead Mad Titan and the zombified giant, the universe of What If...? Episode 5 is almost certainly doomed.
To see Hope Van Dyne's big sacrifice, the newest episode of What If...? is streaming now on Disney+. New episodes are available every Wednesday.