WARNING: The following contains spoilers for WandaVision Episode 8, "Previously On," streaming now on Disney+.
A show as deft at storytelling as WandaVision is just as good in its big showy set pieces as it is with its subtle winks to the audience. Throughout the series, fans lose their minds after every Easter egg and oblique reference that could possibly turn into something greater, and in the latest episode, Agatha Harkness dropped a detail that could potentially change the entire Marvel Cinematic Universe by proving mutants already exist.
The episode largely revolves around a deep dive into Wanda's backstory as Agatha seeks to understand the source of her immense power. Gaping in wonder at Wanda's ability to perform magic on such a colossal scale, Agatha walks through Wanda's memories in an attempt to discover just where that power came from. The tour includes visits to Wanda's childhood, her experimentation at the hands of Hydra and her relationship with Vision, from its blossoming to the android's death. There is so much going on that it might be hard to pick up on the subtle nod to mutants that Agatha drops.
Ever since Wanda's origin in Age of Ultron, it was clear that her initial anti-Avenger motivations resulted from the near-death experience she and her brother had in Sokovia. Trapped under rubble staring down a missile from Stark Industries that could detonate at any moment, Wanda considered herself lucky that the weapon was a dud. After her radicalization, she subjected herself to Hydra's experiments with the Mind Stone, which were originally believed to be the source of her and her brother's powers. However, it turns out there was a deeper story taking place.
In visiting Wanda's childhood, Agatha points out the immensity of the coincidence that involved the Stark weapon never detonating. She reframed Wanda's powers not as resulting from the Mind Stone but being a natural aptitude for "hex magic" that would have "withered on the vine" if the Mind Stone didn't empower them further. It's a very slight hint, but it does not take much to draw the connection between the inborn powers Agatha identified and the X-Gene that serves as the precursor to mutant abilities in the comics.
Under such an interpretation, mutants could have been around for generations, with their powers being so slight and subtle that they are rarely recognized. Significant trauma or exposure to sufficient power sources like an Infinity Stone can catalyze the X-Gene, activating it into a recognizable superhuman ability. This would not only tie Wanda and Pietro's origins back into their mutant history from the comics but also create an easy method by which mutants exist in the MCU without requiring some massive shift in reality.
For Wanda, her origins clearly go deeper than simple mutant powers. Agatha identifies her as the "Scarlet Witch" and ties her into the larger magical elements of the MCU, but for her brother Pietro, the explanation can be as simple as an activated mutant gene. Separate from all of Wanda's reality-altering antics, Pietro is simply a speedster whose powers activated upon exposure to the Mind Stone. Under similar circumstances, a mass event, perhaps encouraged by Wanda herself, could awaken the genes within the rest of the mutant population. The X-Men finally have a clear path into the MCU, and they WandaVision to thank for it.
Written by Jac Schaeffer and directed by Matt Shakman, WandaVision stars Elizabeth Olsen as Wanda Maximoff/Scarlet Witch, Paul Bettany as Vision, Randall Park as Agent Jimmy Woo, Kat Dennings as Darcy Lewis, Teyonah Parris as Monica Rambeau and Kathryn Hahn as Agnes. New episodes air Fridays on Disney+.