Doctor Octopus (Marvel's Spider-Man)

"Parker: We've been focused on limb replacement - connecting nerves at severed extremities, replicating the function of lost appendages. But what if instead, we gave people something they've never seen? Something.. straight from the mind? Unchain all of us from the bodies we've been born with and unleash the awesome power of our minds?"

- Otto Octavius's message to Peter Parker on a recorder.

Doctor Octopus is the main antagonist of Marvel's Spider-Man. He is Peter Parker's science teacher and partner but eventually becomes the supervillain known as Doctor Octopus. He is also the true leader of the Sinister Six.

One of Spider-Man's most famous and notorious foes, Doctor Otto Octavius was a brilliant scientist who invented a set of mechanical arms controlled by a brain-computer interface. After a radiation accident, the four-armed device fused to his body, and he turned to a life of crime.

History
In his youth, Otto Octavius was friends with Norman Osborn. Together the two eventually started a business company known as "Oscorp" (inspired by a nickname others had given them). However, as Norman became more and more obsessed with genetics, the two had a falling out.

Eventually Otto left in exchange for a settlement; money to further his research. Later, Otto began working at Horizon High, where May Parker recommended her nephew Peter Parker to work with him.

Hiring Parker solely on May's words, he began teaching the young student, unaware the student was also the secret identity of the superhero Spider-Man.

During one of their experiments with robotic arms, Norman Osborn's team shut sdown Otto Octavius' and Peter Parker's lab and cuts his grant, due to the site being declared a safety hazard due to a recent accident. Otto insists his previous safety violations were excused, by Norman reminds him that he was the one who excused it and that Otto's equipment should have been confiscated long ago. Norman insists both Otto and Peter work at Oscorp from then on, but Otto rejects his offer.

Shortly after, Otto reveals to Peter that he is suffering from a genetic neurodegenerative disease that is gradually causing his muscles to lower in quality and efficiency. This is a primary running reason for his research and motivations, and his motivation into focusing on mental linkage with his prosthetic designs that take a turn for the worst.

Later, Otto presents Peter four tentacle-like arms attached to his back. The arms are powers by an external prognosis controlled by his brain and can react under one nanosecond. However, Peter discovers that using this method can potentially have severe damage on Otto's psychosis. Otto ignores Peter's warnings and tells him that this is the first time in his life he doesn't feel like a failure, but Peter is able to talk him down into deactivating the robotic limbs. As Peter leaves, Otto sees Norman Osborn on a television telling the citizens of New York to cast their vote to him in the upcoming election. In anger Otto calls Norman a liar and destroys the television with one of his robotic limbs.

With his new arms, Octavius attacks both Ryker's Island and the Raft as "Doctor Octopus", releasing all of the prisoners within including Mister Negative, Electro, Vulture, Rhino, and Scorpion, with whom he forms the Sinister Six. He also steals the Devil's Breath from police custody and releases it in Times Square, infecting hundreds of thousands of New Yorkers, including Peter's Aunt May. With the combination of the outbreak and the mass escape of criminals, the city of New York quickly falls into chaos. Peter goes to apprehend his escaped enemies, quickly rounding up Electro, Vulture, Rhino, and Scorpion while Mary Jane searches for the Devil's Breath cure Oscorp is seemingly working on. She breaks into Norman’s penthouse and learns that his son Harry is terminally ill and that the Devil’s Breath was actually designed as a cure for his condition. After discovering his secret lab, Mary Jane learns that Martin Li was one of the test subjects for the Devil's Breath which granted him his powers. This however ended in tragedy as Li had accidentally killed his parents, sparking his grudge against Osborn. Mary Jane soon learns the location of the cure and informs Peter. After convincing Sable that he is trustworthy, Peter heads to the lab and defeats Li, but Octavius arrives and takes both Osborn and the cure, leaving Peter critically wounded.