For more than 50 years, Spider-Man has abided by one of the comic book world’s most famous mantras, “with great power comes great responsibility.” This saying was born from the moment when Spider-Man, aka his civilian identity, Peter Parker, spitefully refuses to stop a petty burglar from a robbery because it wasn’t his “job.” When the burglar comes back to kill Parker’s Uncle Ben, the teenager’s arrogance goes on to haunt him for the rest of his life and leads him to vow to live the life of a hero, regardless of the personal cost and inconvenience.

But Parker has also adopted certain limits to his responsibility. For example, despite how heinous the criminal he apprehends or how personally the villain harms him, Parker has always refused to cross the unspoken hero moral code and use his power to intentionally kill another living being.

Parker’s interpretation of power/responsibility has come under renewed analysis in the pages of Dan Slott’s Superior Spider-Man, courtesy of one of Spider-Man’s most nefarious foes, Doctor Octopus, aka, Otto Octavius. Since the publication of Amazing Spider-Man #700 last December, the Spider-Man character has been played by Otctavius, who switched brains and bodies with Parker (Parker subsequently “died” inside of Octavius’ body at the end of ASM #700 and after returning in spiritual form, was seemingly eradicated again in Superior Spider-Man #9).

As a villain, Octavius has the blood of dozens on his hands and tentacles, people he has killed during casual crime sprees, and countless others who have come seconds from death via mushroom cloud when Doc Ock attempted to conquer New York City and the entire world in order to prove his physical and intellectual superiority over the human race. Yet as the Superior Spider-Man, Octavius has inherited Parker’s memories and his moral code, vowing at the end of ASM #700 that he too would live by the great power/great responsibility mantra.

During his initial trial as Spider-Man, Octavius has the astral form of Parker steering his actions as a pseudo-Jiminy Crickett, often preventing him from “crossing the line” and doing something “regrettable.” But the spirit of Parker is unable to prevent Octavius from doing what he believes is truly the responsible course of action to deal with the serial killing villain Massacre, in Superior Spider-Man #5.

A creation of Slott in 2011, Massacre is presented in his appearances as soulless killing machine with extreme mental and emotional deficiencies. In Superior Spider-Man #4, Massacre coldly murders long-term supporting cast member Ashley Kafka, a doctor who had treated a number of major villains at the Ravencroft Institute, including Doctor Octopus himself, with varying degrees of success.

After murdering Kafka, Massacre continues his killing spree before settling on bearing his arms inside Grand Central Terminal, before the Superior Spider-Man is there at the scene to save the day. With Parker’s spiritual essence there to try and guide him, Octavius finds that Parker’s way is preventing him from adequately apprehending the criminal. “Stop it! Someone was back there! You let him get it!” Astral Parker cries out in dismay. Octavius thinks to himself “I could’ve ended this! Focus!”

Octavius takes the fight directly to Massacre and disarms him. He then uses one of the killer’s own guns against him to injure him and gain the upper hand. Octavius then has a definitive choice he can either use a gun to end the threat of Massacre once and for all, or do what Spider-Man has done countless times before and web him up and leave him for authorities.

Octavius contemplates these options, seemingly anguished by his choice. If he leaves the serial killer to authorities he wonders if he’ll have to “wait till you break out and kill again … capture you again over and over …” For the first time in his comic book existence, Massacre shows emotion, admitting his “scared.” Astral Parker sees this as evidence enough that “that’s why we don’t kill! ‘Cause there’s always hope.” And yet, Octavius chooses to end the debate and pull the trigger and point blank range.

It’s a watershed moment for the character who has seemingly had justification to kill in the past. During Gerry Conway’s renown “Death of Gwen Stacy” arc in Amazing Spider-Man #121-122, Spider-Man’s arch nemesis murders Parker’s first true love, Stacy, by throwing her off the Brooklyn Bridge (though it’s actually Spider-Man’s webbing that snaps the girl’s neck an kills her).

In the ensuing confrontation, Spider-Man/Parker vows he’s going to end the Goblin once and for all, but when faced with the opportunity to do so, he relents. Despite tracking the Green Goblin down like a relentless dog, and then beating him within inches of his life, Spider-Man stops himself before landing a death blow, admitting if he were to go any further, “I would have become like him – a murderer.”

When Goblin ultimately impales himself on his own glider, Spider-Man bemoans that the death of someone so evil should have “mattered” and made him feel better after the death of Gwen. Alas, he feels no better for the incident.

In the beloved 1985-86 Peter Parker: The Spectacular Spider-Man arc, “The Death of Jean DeWolff,” Peter David pulls Spider-Man/Parker closer to violating his own code than any writer previously. In this arc, a gun-toting madmen, the Sin Eater, kills police captain Jean DeWolff in cold blood. With the help of another superhero, Daredevil, Spider-Man hunts down the Sin Eater in hopes of revealing his identity and bringing the murderer to justice. When Parker discovers the Sin Eater is actually another New York City cop, Stan Carter, he goes into a violent rage, nearly beating the character to death.

With his Superior Spider-Man character, Slott clearly draws inspiration from David for his Massacre confrontation. But instead of Astral Peter serving as the moral compass for Octavius, in Spectacular #110, Daredevil physically intercedes before Spider-Man can do something he may eventually come to regret.

“He might still get loose, kill someone. It won’t be over …” Spider-Man cries out before Daredevil finishes his sentence, “until he’s dead?” Then, in words that Astral Parker would echo years later, Daredevil tells Spider-Man, “you tried to supplant [the justice system]. Be judge jury and executioner rolled into one. I don’t know all the answers, but that isn’t one of them.” Similar to Octavius, Spider-Man pushes back against his fellow hero, telling him not to compare him to the Sin Eater. But unlike Otto, Spider-Man’s hot-headedness, and perhaps the unfamiliar terrain he was treading him, prevents him from finishing his adversary.

Later in the story when Carter is being taken to prison, Spider-Man is ready to turn his back when a mob arrives ready to punish the Sin Eater without the benefit of the trial. But once Daredevil is overtaken by the crowd and cries out for help, Spider-Man’s old instincts take over. He stops DeWolff’s stepfather from strangling Carter. “If I had any choice fela, I’d help you … besides I’m one of the good guys,” Spider-Man says. He is a hero who doesn’t take lives, regardless of how low and demented they are. The fact that Octavius eventually breaks this rules in Spider-Man’s body, makes the killing seem that much more abhorrent.

But Octavius has his justifications for why he chose to do the previously unthinkable to Massacre. During a confrontation with Parker inside Otto’s mind in Superior Spider-Man #9, Octavius tells his accusatory adversary, “And what of Massacre? You let him live last time … and when he returned he killed over thirty people … including your friend Ashley Kafka.” After making Parker face some more of his sins, Octavius throws the former hero’s own mantra against him while defending his otherwise questionable actions, “Power and responsibility, remember? You don’t deserve to Spider-Man. You understand that now.”

Octavius may have a point. In future issues of Superior Spider-Man, the reader learns that since Doc Ock has taken over for Parker, crime is down across the city. New York City Mayor J. Jonah Jameson, one of Spider-Man’s harshest critics the past 50 years, now views the now hardened hero as a true asset to law enforcement. Other New York City cops are looking the other way and protecting Spider-Man when being question about the hero’s role in Massacre’s killing.

And yet, tradition is tradition for a reason, and a comic book character doesn’t go about acting a certain way in thousands of comic book appearances since 1962 if there was something abjectly wrong in the way he does his superhero business. The idea that Spider-Man’s responsibility also applies to the sanctity of even the scummiest life is what has always differentiated the character from some of Marvel’s other anti-heroes like Wolverine (who has committed some heinous acts himself in the Age of Ultron miniseries). Spider-Man may have flaws that prevent him from earning universal love and adoration across New York and the world, but one thing he’s never been until now is a murder.