What makes Spider-Man a good hero? The answer is a multi-faceted one, but can best be boiled down to Uncle Ben’s famous words of wisdom - "With great power, there must also come great responsibility." That’s why the physically and mentally superior Spider-Man can’t just go about beating bad guys into paste - he’s honor-bound to use his amazing abilities responsibly.
So, why do so many images exist on the internet of Spidey committing horrific acts of violence? The answer, as with comic books themselves, can get a bit complicated. It can best be summed up as a blend of bad decisions, alternate realities, and body-swapping villains. Just another day in the life of your Friendly Neighborhood Spider-Man.
Kaine Parker was once a “corrupted” clone of the original Spider-Man, and he came with a matching set of spider-powers - including an acidic touch derived from Spidey’s wall-crawling abilities. During the events of the Spider-Man: Grim Hunt, Kaine ends up sacrificing his life to save Peter from the family of Kraven the Hunter. An enraged Spidey ironically hunts Kravinoff and his family down and dispatches some savage vengeance - a rampage that includes ripping the skin off of Kraven’s daughter’s face in a twisted tribute to the late Kaine.
This is Peter Parker at his most vicious, so much so that it borders on “out of character” territory.
The concept of the Marvel Zombies series is rather simple - a classic zombie virus infects an alternate version of the Marvel Universe - but the results are gruesome. The bad behavior spreads as more and more super-powered people get transformed into the walking dead, including the Friendly Neighborhood Spider-Man.
In a scene too difficult for most to read, the zombified Peter Parker turns on his wife, Mary Jane, and his beloved Aunt May, and devours them. To make matters worse, the Marvel Zombies version of the undead retain their memories, so Zombie Spidey has to live with what he’s done.
Spider-Man accidentally killed a KGB spy named Charlie during an adventure with Wolverine, and he didn’t take it very well. One issue of What If? Spider-Man Versus Wolverine, though, explores what might happen if he mishandled the situation entirely. This version of Spidey leans into his newfound lethality, as he cuts a bloody swath across Europe, killing those responsible for Charlie’s persecution - including terrorists and supervillains, like the Crimson Dynamo.
This dark alternate Spidey even hides guns in his web-shooters and uses one of them to dispatch the Swordsman coldly.
The Superior Spider-Man - Otto Octavius - does a wonderful job of making Spider-Man look like a corrupt and maniacal villain. Technically, he’s still a superhero of sorts - albeit, an incredibly violent one. Whereas the original Spidey would never use his super-strength against non-powered individuals, Doc Ock has no issue dealing out horrific injuries to even the lowliest of villains. He even installs claws on his fingertips and uses them to vicious effect against Jester and Screwball, a couple of costume-wearing YouTube pranksters.
It’s not exactly a sign of restraint on the part of Octavius, and it’s a far cry from the typical behavior of the Friendly Neighborhood Spider-Man.