The Sinister Six is a team of super-criminals in Marvel's Spider-Man. Led by Doctor Octopus, the group consists of Mister Negative, Electro, Vulture, Rhino, and Scorpion. Doctor Octopus forms the group in an attempt to take revenge on his former business partner, Norman Osborn, and they clash with Spider-Man when he interferes.
After Mayor Osborn claims credit for the capture of Mister Negative, this infuriates Otto Octavius and pushes him over the edge. Osborn had already removed funding from his projects at this point and, according to Octavius, stolen his ideas and technology. Past history showed that, while they had worked together as scientists and co-founded Oscorp, Osborn was quick to break the rules, such as when he used an untested substance called "Devil's Breath" on a young Martin Li and inadvertently created Mister Negative.
Octavius assumes the mantle of Doctor Octopus to exact his revenge, breaking criminals out of Ryker's Island and the Raft. He had researched all of the most violent, offering each of them something unique if they were to help him. For Scorpion, he would clear Gargan's remaining debts and expunge his criminal record. Octavius also develops a corrosive agent that would free Rhino from his suit, which according to Peter a certain government agency had been trying to do for years, the process of which only takes Octavius a few days. Vulture, who now suffers from spinal cancer due to the power source for his wings, is offered a new form of treatment by Doctor Octopus. Finally, Octavius gives Electro a newly modified version of his harness to get him closer to becoming "pure energy", which is Electro's dream. Thus, they form the Sinister Six, with the singular goal of destroying Mayor Osborn and Oscorp. The group first clashes with Spider-Man when they gang up on him at the Raft; Doctor Octopus warns Spider-Man to stay out of their way and throws him off the edge of the Raft.
Afterwards, Vulture teams up with Electro and together they set up a trap for Spider-Man, although he manages to defeat them. He then has an encounter with Scorpion, who poisons him. After having to fight against the hallucinations of his own mind and barely escaping, Spider-Man has a second encounter with Scorpion, who is now accompanied by Rhino. He ultimately defeats the duo, leaving only Mister Negative and Doctor Octopus left. Spider-Man finds Mister Negative inside the Devil's Breath lab, where Li attempts to kill Osborn. After defeating him in the resulting battle, Spider-Man is confronted by Doctor Octopus, who soundly thrashes him and recaptures Osborn. To fight the supervillain, Spider-Man builds an armored version of his suit via materials that were used to create Doctor Octopus's mechanical appendages. He then rescues Osborn before engaging in a showdown with Doctor Octopus atop Oscorp Tower, where Spider-Man defeats him.
- Doctor Octopus (Otto Octavius) (founder/leader)
- Mister Negative (Martin Li) (second-in-command)
- Electro (Maxwell Dillon)
- Vulture (Adrian Toomes)
- Rhino (Aleksei Sytsevich)
- Scorpion (MacDonald Gargan)
The Sinister Six first appeared in Amazing Spider-Man Annual #1 (October 1964).