Marvel Comics reveals that if Spider-Man hadn’t given up the black symbiote suit that would later be known as Venom, he would have suffered a grizzly fate as Venom’s original plan for Spider-Man is genuinely horrifying. Spider-Man first wore the black symbiote suit when he found it on Battleworld during Marvel Comics’ Secret Wars event. In a timeline where the heroes never made it off Battleworld and instead made a life there, Spider-Man never takes off the symbiote costume and becomes consumed by its darkness, literally.
In What If…? #114 by Jay Faerber and Gregg Schigiel, the heroes and villains who fought on Battleworld including Wolverine, Storm, Thor, Captain America, Iron Man, Doctor Doom, and Spider-Man formed a life there rather than making their way back to Earth like in the original Secret Wars storyline. This issue picks up twenty-five years after Secret Wars and many of the original participants have had children within that time, including the villainous Doctor Doom. Doctor Doom’s son, Vincent von Doom aka Malefactor, assassinates his father as he plans to return to Earth and conquer it. When the other heroes find out about Vincent’s power-play, they assemble and attack Malefactor and his small army.
During the battle between the Avengers and Malefactor, black suit Spider-Man is shot with sonic blasts, revealing the truly horrifying truth of what has become of Peter Parker after wearing the Venom symbiote for more than two decades. When blasted with high-frequency sound waves, the symbiote extends from Spider-Man’s body in pain and as it does so fans are shown that Peter Parker’s body is nothing but a skeleton. The Venom symbiote consumed Spider-Man’s flesh and has taken over his life by remaining wrapped around his skeletal frame. Since the What If…? storylines aren’t separate universes but skewed timelines of what could have happened in the main 616 universe, this disturbing outcome could have happened to the Spider-Man of Marvel’s main continuity if he hadn’t removed the suit.
It is unclear why the symbiote literally ate Peter Parker in this timeline and never did so to the many other hosts Venom has worn in the time since the symbiote was in possession of Spider-Man. The best reasoning one could draw is that because of Spider-Man’s powers, the symbiote was so overwhelmed with how perfect a host he was that it couldn’t stop itself from absorbing every part of him until it finally destroyed his body altogether.
As fans are aware, a symbiote collects samples of its host's consciousness into a codex and stores that information for the rest of its life. Since Spider-Man never wanted to get rid of this costume as it made him even more powerful than he already was and he was stuck on an alien world, it simply kept collecting data for twenty-five years until there was nothing left of the original Spider-Man except his skeleton, a grim reality that proves Venom’s original plan for Spider-Man was genuinely horrifying.