Earlier this year, rumours started swirling that Mysterio was set to make a cameo appearance in What If...? season 3. Considering the complicated nature of Marvel Studios and Sony Pictures' deal to share Spider-Man, it was undeniably hard to believe.
Well, as you can see in the screenshot below (via ComicBookMovie.com), Mysterio shows up in the first trailer for the show's final season and is hooked into an extremely dangerous-looking device.
Spider-Man: Far From Home was released before the Multiverse Saga began, introducing Quentin Beck, a Multiversal warrior whose home had been decimated by monstrous Elementals. He was later revealed as a fraud and a disgruntled former Stark Industries employee eager to get his hands on the recently deceased Tony Stark's tech.
However, the fact he gave the MCU the designation of Earth-616 raised some eyebrows as did the fact his comic book counterpart once found a way to hope between the main Marvel Universe and the Ultimate Universe.
Might Mysterio's presence in What If...? be used as a means to retcon Spider-Man: Far From Home, revealing that Beck survived his run-in with Spidey? It's certainly possible he was telling the truth about hailing from another reality, though we'd suggest bracing yourselves for the possibility this is just a random Variant.
Concept art has confirmed Marvel Studios considered bringing Mysterio back for Spider-Man: No Way Home, a decision which would have been embraced by fans eager to see him tied to the Multiverse in some way.
In 2022, Spider-Man: No Way Home writer Chris McKenna confirmed that Jake Gyllenhaal was among the actors they reached out to. However, the decision was ultimately made that not everyone could appear here, so Quentin Beck was dropped.
"When it actually started coalescing, when feelers were put out and actors were like 'Yeah, I'm game for that.' Then it became this overwhelming thing because you're like, 'Okay, this is the reality now,'" he explained. "You can't just be swimming in a million characters, you have to be choosing characters wisely and making sure that they don't overwhelm the story and Peter himself."
For what it's worth, Gyllenhaal has always spoken fondly of his time in the MCU and hasn't closed the door on possibly reprising his role.
"It was such a cathartic thing to be able to throw away all that seriousness and really become the actor that I think I've always wanted to be," Gyllenhaal said in 2022. "I think that we go through journeys in our life where we're finding ourselves, and in the case of Spider-Man, I think I realized 'hey, acting is really fun, you know, enjoy it!'"
Whether the actor returns to voice Beck in What If...? season 3 remains to be seen.