Spider-Man: Into the Spider-Verse 2 needs some bad Spider-People -- not bad as in quality, but bad as in not very nice. It's remarkable how every Spider-Man in the first film was a good, cheerful character with a noble heart. While that was important for Into the Spider-Verse and helped keep everything on track, the sequel needs at least one Spider-Person who likes to get his hands dirty.
While Superior Spider-Man might be a tempting candidate, a few better ones would be Venom, Spider-Carnage or the Doppelganger, particularly when it comes to imaginative designs. While Venom remains one of the most prolific characters in superhero media, the other two are highly under-utilized characters who might have a chance to shine in the upcoming sequel. Plus, Spider-Carnage already starred in a Spider-Verse story as the main antagonist -- in a way.
Venom
Most modern audiences seem to love Venom. The recent Tom Hardy-led film surpassed expectations financially and ended with a tease for the then-upcoming Into the Spider-Verse. While that post-credit scene teased the impending animated film, Venom didn't tie into Spider-Verse at all. But it honestly should have.
Venom in many ways is a foil to Spider-Man, with all the power but a twisted sense of responsibility. It also doesn't help that, like Peter B. Parker, the Venom established in the SUMC is also a disaster who is down on his luck and struggling to hold onto a sense of order. But regardless, even if the Venom in the film is more of a unique spin on the character unconnected to the live-action films, Eddie Brock still serves as a terrific adversary for Spider-Man.
Regardless of whether or not the Venom in Spider-Verse 2 is tied in with the live-action film, Hardy should still lend his voice talents to portray him. Hardy's take on Eddie/Venom remains one of the highlights of the 2018 smash hit. If the upcoming sequel wants to draw in an even bigger audience than its predecessor, the powers to be should include Tom Hardy in the project as his manic anti-hero.
Black Suits
Another potential contribution Venom can bring to the story is the color of his Symbiote. Black Suit Spider-Man remains one of the coolest Spider-Man designs around. With the infinite potential of the Spider-Verse brand, it seems peculiar not to utilize the black suit in some capacity.
The Symbiote tends to corrupt and manipulate the host, offering the opportunity for characters, when faced with difficult choices, to actually struggle to make the right decision. Worse still, they might make the wrong decision, sending the plot spiraling in drastic, dramatic directions.
Even if Eddie Brock doesn't appear, one of the Spider-Men should have the Black Suit. It can spread from hero to hero, offering views of characters we'd otherwise never see, like Gwenom. All in all, even if the Symbioyr serves no plot specific function, it would just be aesthetically pleasing for audiences.
Spider-Carnage
The logical extreme of the earlier point is Spider-Carnage, a character who has appeared only a few times over his brief comic history. However, each appearance of Spider-Carnage is an event. The two most famous versions of Spider-Carnage have ties to the Clone Saga, with the first being the 616 Ben Reilly overtaken by the Carnage symbiote. The second, from the 90s animated series, is Peter Parker, who, convinced he's the clone to his world's Ben Reilly original, is overtaken by the Carnage symbiote, which at this point in the series was trapped between dimensions.
In the case of the first Spider-Carnage, the symbiote tried to control Reilly, though Reilly, fighting for control, breaks free. In the case of the animated series, however, Spider-Man willingly becomes Spider-Carnage, using both his knowledge of inter-dimensional travel and his existential depression to concoct a plan to eradicate all realities at once.
In the finale of the animated series, the Kingpin is ultimately responsible for Spider-Carnage's creation by helping create interdimensional technology. This is akin to how Kingpin uses the Super Collider in Into the Spider-Verse to attempt to bring an alternate version of his family into his reality.
But while that origin is consistent with what's been set-up win Into the Spider-Verse, why include Spider-Carnage at all? Simply put, it will allow us to see Spider-Man unshackled. Should a Spider-Man lack any moral limitations, what might they do? Should they be driven to even further madness, what could they accomplish? While this is similar to what could be done with a black suit Spider-Man, the benefit of Spider-Carnage is that it would put on-screen something fans have never seen before.
The Doppelganger
However, there is a possibility that Into the Spider-Verse 2 will never cover themes that really allow an evil Spider-Man to appear. In this event, the solution is simple for an evil Spider-Man: throw in the Doppelganger.
The Doppelganger is a bizarre alternate reality clone of Spider-Man, one created during the comic Infinity War event. This story saw the creation of several clones of established Marvel heroes. Spider-Man's Doppelganger survived thanks to the arrival of Demogoblin, who managed to preserve him even as the other clones collapsed. What remained was a mindless clone -- the perfect, chaotic henchman for any villain who treated him with a degree of kindness.
So what good would Doppelganger serve in this story? Simply put, the Doppelganger offers the possibility of an evil Spider-Man for the heroes to fight that will require no effort. You throw the monster on-screen as just a mindless Spider-Man from another universe, and you have a fun henchman who has next to no required character development. He's just a perfect punching bag, with a killer look to accompany him.
Doppelganger can also represent the juxtaposition of a character fighting the dark shadow version of themselves, as a metaphor for a character's potential destructive power manifested in the flesh. With a wide range of Spider-People to choose from, an alternate version of any of the previously introduced Into the Spider-Verse heroes could bring an interesting wrinkle to the upcoming sequel.
Ultimately, all these evil Spider-People represent the ideal foil for each of the heroes. With each version of Spider-Man being the idealized, best version they could be, these dark shadows can offer a real open-world of possibilities. After all, if there are an infinite number of universes and an infinite number of Spider-Men, not all of them will be your friendly neighborhood hero.