Spider-Man has the best rogues’ gallery in comics this side of Batman, but at the core of it lies an intense rivalry that has taken many forms over the years: Spider-Man vs. Doctor Octopus. That’s right, it is Otto Octavius - and not Norman Osborn, the Green Goblin - who is, and always has been, Peter Parker’s greatest enemy.
Having made his debut back in 1963’s Amazing Spider-Man #3, Marvel Comics’ Doctor Octopus has been plaguing the wall crawler for nearly his entire existence, and during that time, he’s done more damage to Spidey than any old Goblin ever could. Doc Ock has slain Parker’s friends, swindled his webslinging identity, and even tried to marry his beloved Aunt May - and he did it all with nothing more than his own wit, ingenuity, and custom-made mechanical arms.
Norman Osborn - in his guise as the Green Goblin - is notable for being the first supervillain to discover Spider-Man’s secret identity and use it against him. With that being said, it wasn’t that grand of a feat, considering that Osborn already had a close personal relationship with Peter Parker - and that Otto Octavius had already unmasked Spidey in his third-ever comic book appearance.
Way back in 1964’s Amazing Spider-Man #12, Doctor Octopus beats up Spider-Man in front of a crowd and removes his mask. Fortunately, Parker was suffering from a virus at the time and put up such a pathetic fight that Doc Ock - and everyone else present at the time - reasons that he couldn’t possibly be the real Spidey. Eventually, the wall crawler returns to health and clobbers Octavius, but that doesn’t change the fact the villain was one realization away from ending Spider-Man’s vigilante career shortly after it began.
The Green Goblin has built his reputation on the slaying of Gwen Stacy, and with good reason - aside from Uncle Ben, the loss of Gwen has probably had the greatest emotional impact on Parker’s life. Once again, however, Octavius beats Osborn to the punch when it comes to Stacy-slaying in Amazing Spider-Man #90.
Throughout the course of Parker and Gwen’s relationship, Parker develops a bond with her father, Captain George Stacy, who becomes a surrogate father figure of sorts for the young superhero. During yet another clash with Spidey following yet another break from prison, Doctor Octopus knocks over a rooftop chimney onto the observing crowd below, and George bravely pushes a child out of the way, perishing as a result. Though the incident is ostensibly a mishap, it still results in extreme emotional turmoil for Parker and the people he most cares about.
Osborn has tried to slay Spider-Man on numerous occasions, but he’s never quite succeeded, despite having caused great harm to some important people in Parker’s life. In fact, the Green Goblin has only ever perished himself in conflict with the webslinger, whereas Doctor Octopus has actually finished the job.
The events of Dying Wish see a terminal Octavius pull off the ultimate switcheroo: swapping his mind with Parker’s, and thus trapping his greatest enemy inside his own failing body. The two fight while piloting each other’s body, and in the end Parker meets his demise when Ock’s heart gives out - though not before imparting some important lessons about power and responsibility to the newly minted Superior Spider-Man.
The Red Goblin saga features a truly terrifying combination: Osborn wearing the Carnage symbiote. The titular villain goes on to terrorize Spider-Man and slay Flash Thompson, but in the end he is dominated by the alien costume - to the point that, at the end of it all, Osborn is left asylum-bound and believing himself to be Cletus Kasady, the lunatic serial slayer most commonly associated with the symbiote.
It’s thus fair to say that Octavius’s own experience with a symbiote - in the midst of his run as the Superior Spider-Man - goes significantly better. After taking the Venom suit from Flash Thompson, Octavius becomes the Superior Venom, and manages to keep better control over the alien’s impulses than most. When his methods become even more cruel, however, the Superior Venom draws the attention of the Avengers, who he very nearly defeats single-handedly before giving up the symbiote.