When the Spider-Man: No Way Home trailer finally landed, it delivered on fan hopes, confirming Tom Holland's third solo outing in the Marvel Cinematic Universe will indeed dive into the multiverse and revive Spider-Man foes from earlier incarnations of the franchise. Most notably, the trailer ended by revealing the return of Alfred Molina's Doctor Octopus, a role the actor hasn't played since 2004's Spider-Man 2, opposite Tobey Maguire. He will be joined by Jamie Foxx's Electro, last seen in 2014's The Amazing Spider-Man 2, but the footage also teased the return of Sandman, the Lizard and the Green Goblin.
With so many supervillains gathering to menace Spider-Man in the finale to his first MCU trilogy, it seems likely Marvel Studios is creating a multiversal version of the Sinister Six. In the comics, the Sinister Six were a team of Spider-Man's deadliest enemies -- originally Doc Ock, Sandman, Vulture, Electro, Mysterio and Kraven the Hunter, although various iterations of the group have been seen since -- who joined forces to take on the wall-crawler. With only five potential members glimpsed in the trailer, fans have been left wondering: who is number six? There are a few potential candidates.
The Scorpion
Mac Gargan made his MCU debut with a minor role in 2017's Spider-Man: Homecoming, buying weapons from the Vulture. Comic book fans know Gargan originally went on to become the Scorpion -- a super-strong menace encased in a deadly armored suit, engineered specifically to kill Spider-Man. The Scorpion's creation was bankrolled by J. Jonah Jameson, which could make No Way Home the perfect time to introduce him. Spider-Man is now believed to be a murderer and Jameson is leading the media campaign against him. Having him fund the creation of the Scorpion to combat Spider-Man could bring Jameson into the plot in a more meaningful way and offer a payoff to Homecoming's mid-credits scene, which saw Gargan in prison, eager to exact his revenge upon the hero.
While it would make sense to introduce the Scorpion now, there may be one issue preventing the character from appearing. The film seemingly also features the Lizard, glimpsed in one fleeting shot in the trailer, and the two are very visually similar. Both are hulking, green figures with tails and it's likely the filmmakers will want to make each member of the Six as distinct as possible. However, given how briefly (and dimly) the Lizard is seen in the trailer, there is a possibility that is Scorpion. But if so, that still leaves a sixth spot vacant.
Venom
Eddie Brock's symbiotic alter ego is probably the least likely candidate on this list. Time and time again, rumors of a crossover between Tom Hardy's Venom and Tom Holland's Spider-Man have been denied. However, the trailer's total lack of a sixth villain may suggest the final member of the Sinister Six is an even bigger surprise than Molina's Doc Ock. For months before the trailer was released, rumors were swirling of No Way Home involving villains from previous Spider-Man franchises, but a crossover with Sony's new Venom films would come as a real shock -- one neither studio would want to spoil.
Involving Venom might also offer an opportunity to explain how Sony's Spider-Man Universe and the MCU overlap, a topic that has raised questions in the fanbase ever since a key Homecoming character appeared in the trailer for Sony's upcoming Morbius.
The Vulture
Michael Keaton's Adrian Toomes was Spider-Man's first major enemy in the MCU, appearing in Spider-Man: Homecoming. As Toomes survived the events of that film, appearing in the post-credits scene with Mac Gargan, rumors of a return have been swirling ever since. True, in that post-credits scene the Vulture chose to keep Peter's identity a secret, suggesting he felt he was in the wall-crawler's debt after Spider-Man saved his life, but maybe his feelings have soured after a spell behind bars. Or maybe No Way Home features an entirely different Vulture altogether.
Keaton is reprising the role in Morbius, a Sony property that may or may not be set in the MCU. If Morbius takes place in another corner of the multiverse, could that universe's Vulture be joining No Way Home?
Mysterio
Spider-Man's previous MCU outing, Spider-Man: Far From Home, saw the death of Jake Gyllenhaal's Mysterio. However, it would not be too great a surprise if the master of illusion is revealed to have faked his death. His demise certainly caused Spider-Man a great deal of strife. In his final moments, Mysterio activated a contingency, releasing a video that framed him as a hero and Spider-Man as a murderer, revealing Spidey's true identity to the world. It's feasible Mysterio faked his death as part of a plan to bring Peter Parker's world crashing down. With the stakes suddenly raised through the arrival of supervillains from across the multiverse, perhaps Mysterio decides to break his cover to help the rest of the Sinister Six finish off Spider-Man for good.
Bringing Mysterio back would give the film's central conflict a more personal emotional grounding. While the villains of other universes may represent a formidable threat for Peter to overcome, they have no shared history with this version of Peter Parker, or indeed anyone on his Earth. Conversely, Mysterio lied to Peter and betrayed him in Far From Home, and that was before he publicly unmasked him and accused him of murder. There's a lot of pain between these two characters, which could make the stakes all the more personal. It could also explain why the film's sinister sixth villain was mysteriously absent from the trailer, as Marvel/Sony would presumably not want to reveal Mysterio's survival just yet. Whoever their final member is, the Sinister Six are sure to give Spidey his greatest challenge yet.
To see who could be joining the Sinister Six, catch Spider-Man: No Way Home in theaters on Dec. 17.