Although he's fought alongside them in other universes, a symbiote-controlled Spider-Man in the Ultimate universe nearly took down his world's version of the Avengers, the Ultimates. Having a turbulent history with Venom and its host Eddie Brock, the past comes back to haunt Peter Parker when both suddenly return into his already chaotic life. When Spider-Man intercepts a battle between Venom and the technological criminal called the Beetle in Times Square, the symbiote leaves Eddie and reclaims Peter against his will. Spider-Man is unable to control himself as the Ultimates arrive, with the famous heroes trying in vain to defeat the unfamiliar threat while not getting eaten in the process.
In the mainstream Marvel universe, Spider-Man discovers his new black costume is actually an alien symbiote attempting to bond to him physically and mentally. His rejection of it leads to the symbiote finding a new host, disgraced journalist Eddie Brock, and their mutual hatred of Spider-Man creates Venom. In the Ultimate universe, a parallel Marvel world that presented opportunities for modernized yet different versions of classic characters or storylines, the symbiote was reimagined as a symbiotic bio-suit that was created by Peter and Eddie's fathers to be a cure for modern diseases. When Peter learns of its existence, his genetic similarities allow him to use it as Spider-Man ,although he would later destroy it. Having learned about everything including Peter's secret, an angry Eddie uses a spare sample of the symbiote to bond with, giving him similar abilities as Peter but requiring him to regularly devour people to stay alive. Spider-Man later confronts Eddie and after a heartbreaking fight, it appears that the new Venom perishes after being electrocuted.
In the "War of Symbiotes" storyline by Brian Michael Bendis, Stuart Immonen, Wade von Grawbadger and Justin Ponsor, Eddie is revealed to have survived, caught up in a situation involving Silver Sable acting on the behalf of Trask Industries, who want their legal property, the symbiote, back. While Venom fights the Beetle, the ensuing battle is interrupted by Spider-Man, whose desire to help Eddie backfires when Peter is forced to become Venom again. While the Wild Pack does nothing to help the situation, the Ultimates drop in and immediately attack the new Venom. Although Spider-Man tries to resist, the symbiote allows him immunity from much of the Ultimates' attacks before he is finally subdued by a lightning bolt from Thor.
Driven by an insatiable desire to feed, the Venom symbiote augments its host's natural abilities and in Spider-Man's case, it makes him strong enough to fight Earth's Mightiest Heroes. When the Ultimates begin their attack, Venom appears immune to Iron Man's repulsor rays, Wasp's bio-electrical blasts, and Hawkeye's arrows. Although Captain America is able to put up a fight, the symbiote shows some intelligence by stealing his signature shield to block further repulsor blasts and even Thor's hammer Mjolnir. Although Peter shows some control in preventing the symbiote from eating Captain America, Fury has to make the tough call to neutralize the threat despite learning Parker has been inside the whole time. He calls Thor, considered one of the world's most powerful heroes, to summon the lightning and the direct hit neutralizes Venom once and for all.
When Peter Parker wakes up, he finds himself in his room in Queens. He later meets with Fury and other Ultimates who confirm they were able to remove him from the symbiote and bring him back home. With the symbiote safely stored in the Triskelion for further study, the Ultimates show no animosity against Peter since they know he was not in control during their battle. Ignoring Spider-Man's warnings to destroy the suit, the Ultimates are lucky that SHIELD's plans for the Venom symbiote do not lead to another incident considering how well their last battle with it went down.