WARNING: The following contains spoilers for What If...? Season 1, Episode 8, "What If... Ultron Won,?" streaming now on Disney+.

The Marvel Cinematic Universe has been exceedingly careful with canon, allowing for several twists and turns that rapidly become fan favorites. Steve Rogers’ spectacular use of Thor’s hammer in Avengers: Endgame, for instance, sprung from a seemingly throwaway moment in Avengers: Age of Ultron, yet the franchise kept the thread consistent for a huge payoff years later. Marvel Studios has gotten so good at continuity that fans readily take it for granted.

The latest episode of What If…? caused a stir on that front with an apparently egregious breach of previous MCU canon. Season 1, Episode 8, “What If… Ultron Won?” features a triumphant Ultron in Vision’s body, using the Infinity Stones of his universe even after he’s breached the walls of his own reality. It’s a noted oversight in part because the MCU is so careful. But as it turns out, the canon-breaking error matters far less than it may seem, and indeed can be viewed as a sign of healthy storytelling rather than the other way around.

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Infinity Stones In Loki

The breach itself is hard to miss, and at the very least requires some significant hand-waving to explain away. Having succeeded in his initial ambitions to wipe out every living creature on Earth, Ultron-Vision quickly takes control of the Infinity Stones and uses them to commit universal genocide throughout his reality. Upon discovering the nature of the Multiverse, he shatters the bonds of his own universe and attacks the Watcher himself, intending to travel to every reality and extinguish all life but his own.

It’s a horrifying plan, but unfortunately, it runs against a strongly established piece of MCU canon. According to the Time Variance Authority in Loki, the Infinity Stones are useless outside of their own native reality. This is supported by instances in the comics themselves, notably in the JLA/Avengers crossover in which Darkseid was prevented from using the Infinity Gauntlet precisely because he comes from a different reality. Loki drove the point home with the stunning shot of multiple Stones – the epitome of power in Loki’s mind – kept in the drawer of a bureaucrat’s desk and literally serving as paperweights.

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Infinity Ultron using the Infinity Stones in What If...?

That puts a crimp in Ultron-Vision’s plans, or rather it should. What If…? plows merrily forward, however, with no signs of Infinity Stone failure. The mad AI launches a full-bore attack with the Stones on Uatu, which continues as they battle their way through multiple realities. It runs in direct contrast to the rules Loki set forth, and presents a conundrum to the MCU going forward. With the Multiverse playing such a huge role in Phase 4, such a contradiction could cause confusion about how it’s all supposed to work.

And there’s nothing wrong with that provided it’s handled in the proper spirit. Continuity errors were all-too-common in the comics industry, caused by anything from printing errors to writer oversight. Marvel even famously developed an in-joke around it, called a “No Prize.” Fans who wrote in offering a sufficiently clever explanation to cover the apparent continuity error would have their letters featured in a subsequent issue, along with an assurance that their “No Prize” was in the mail. The concept was abandoned once fans began taking the exercise too seriously, but for a time, it was a brilliant way for Marvel to poke fun at its occasional mistakes and share the smile with their fans.

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What If…? maintains an odd status among the MCU, owing both to the nature of its stories and its animated format, which might allow enough hand-waving to excuse the error. Countless other explanations exist too, including the notion that Ultron-Vision is sufficiently powerful on his own to wipe out the Multiverse without relying on the Stones. Marvel made up the rules and can add new ones as it pleases to smooth over such contradictions. But ultimately, that doesn’t matter as much as it seems either. Canon is important as a guide and a road map to elaborate properties like the MCU. However, if canon becomes too hidebound, it can restrict good storytelling. The MCU has earned its reputation for clear continuity, and an occasional breach can be readily forgiven. In this case, it helps create a massive threat to the entire Multiverse, giving What If…? the opportunity to end its first season in a spectacular fashion. A little hand-waving is a comparatively small price to pay.

To see Ultron's rise to power, Episode 8 of What If...? is streaming now on Disney+. A second season of What If...? is expected to debut on the streaming service sometime in 2022.

KEEP READING: What If...? Season 1, Episode 8, 'What If... Ultron Won?,' Recap & Spoilers