In the Marvel Zombies universe (Earth 2149) Spider-Man was one of many to be infected with the zombie virus and from there was transformed into a sadistic flesh-eater along with the other former heroes and villains. However unlike most of his peers, who came to more or less accept their fate, Spider-Man was remorseful and self-loathing over the atrocities he'd been a part of, not the least of which was eating his own wife and aunt.
Earth 2149 Spider-Man first appeared taking away a raving Ashley Williams at Colonel America's request. However, once the Avengers were turned into the first zombies Spider-Man panicked and returned home to warn his aunt and wife. Unfortunately, he had already been bitten by Colonel America and succumbed to the virus, making his own family his first victims. Horrified at what he had done but unable to control himself he attempted to kill a visiting Nova and then turned Daredevil into a zombie when he intervened. From there Spider-Man along with most of his former friends became a sadistic predator who devoured any humans he could find, including J. Jonah Jameson (which he did admit to enjoying beforehand).
Eventually though, the zombies ran out of humans to eat, at which point they began making efforts to find a new food source. By this point Spider-Man had lost a leg during the zombie's battle with Magneto, rendering him much less useful in a fight. However, after he and his fellows devoured the Silver Surfer, they acquired his cosmic powers, at which point Spider-Man became a danger once more. When Spider-Man's group developed a means to take down Galactus (who had come to Earth to devour it), they also came into conflict with a group of zombified villains, many of whom were members of Spider-Man's own rogues gallery. During the battle, Spider-Man gleefully murdered his old enemies Venom and the Green Goblin, and also decapitated the Red Skull after he killed Colonel America.
After devouring Galactus and acquiring more of the Power Cosmic from him, Spider-Man and his fellows became the Galacti, and began devouring life across the galaxy. Through it all Spider-Man remained remorseful over his actions, noting how he and his friends had become worse monsters than any of their old enemies had ever been, but also being unable to resist the hunger. After forty years the zombies seemed to run out of food to eat, at which point they decided to go back to Earth to recreate Reed Richards' portal for travelling to other realities. By this point Spider-Man had also gotten a mechanical leg to replace his missing one.
However, by the time the zombies returned to Earth their hunger began to at last dissipate, having finally burned itself out. Spider-Man and Luke Cage were the first to be freed of it's influence, and turned on their fellows, fighting them alongside the humans before the others overcame their hunger as well. Unfortunately, they were then betrayed by Cortez, who sent them to a different reality. Spider-Man for his part ended up in a world akin to the Marvel Universe in it's "early years" (Silver Age).