Warning! Major SPOILERS for WandaVision below.

The climactic showdown in WandaVision's series finale saw Agatha Harkness trying to steal Scarlet Witch's powers. From the moment she revealed her true self to Wanda at the end of "Breaking the Fourth Wall," Agatha demonstrated her obsession with obtaining what she couldn't have. So, she learned how to steal it, over hundreds of years of practice and by studying the Darkhold.

WandaVision's penultimate episode, "Previously On," kicked off with Agatha put on trial in the 1600s by her coven because she was accused of stealing knowledge above her station. She claimed that the coven's rules against dark magic bent to her power, meaning that she had access to a wealth of knowledge. The coven's witches began to blast her with their collective energy. But suddenly, Agatha turned their power against them to drain the life-force out of her coven. This ability is called back to in WandaVision's series finale. When Agatha and Wanda are going toe-to-toe, Agatha absorbs every magical blow Wanda hurls at her. The elder witch seems to absorb the power from each hit, taking a little bit of life and magic from Wanda with it.

Related: What Has Wanda Unleashed? Agatha's Warning Explained

It's not confirmed how Agatha knew how to suck the life out of another being, but it's safe to assume that she learned through her thorough study of the Darkhold, which is Marvel's book of the damned. That likely gave way to her ability to steal magic from another witch. That unpredictable bit of magic gave fans a healthy dose of what to expect for the MCU's Phase 4, and how it will be different than anything they've previously done.

Agatha Harkness WandaVision MCU

Agatha Harkness's powers in WandaVision draw some inspiration from her comic book storyline. In the comics, Agatha draws her power from multiple sources. As Looper writes, those sources are her own internal source of energy, magic that exists within the Marvel universe, and extra-dimensional energy that exists within various entities and objects in tangential dimensions. But as the version of Agatha shown in WandaVision is more villainous than her comic book counterpart, her abilities were tweaked to have her steal magic from others who she deemed unworthy. As Wanda's ability to wield chaos magic stems from raw talent rather than years of study, Agatha decided that she wasn't worthy of those powers.

The chaotic elements of Wanda and Agatha's powers are the perfect introduction for the tonal shift for Phase 4. The first three phases of the MCU focused on the powers of more standard superheroes like Captain America and Iron Man. With projects like Spider-Man: No Way Home and Doctor Strange in the Multiverse of Madness, Marvel has confirmed they will begin to explore the multiverse. That introduces the opportunity for Marvel to get a little more experimental with the properties they adapt. Kicking off Phase 4 with two witches capable of unpredictable and seemingly limitless power means the previously expected beats of past Marvel movies have been thrown out the window. "The Series Finale" ended with Wanda magically reverting Agatha back to her Agnes character and trapping her within the confines of Westview. By doing that, WandaVision kept the door open to bring back Agatha in future installments. That means she can continue to bring a level of chaos and unpredictability that will undoubtedly shake up the MCU for the best.

More: What's Next For Agatha Harkness After WandaVision?

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