Dr. Otto Octavius (Alfred Molina) is a genius in the field of fusion, and lucky for him, his experiments are being funded by Oscorp's current CEO Harry Osborne (James Franco), who took over for his late father. Harry's best buddy Peter Parker (Tobey Maguire) is there to witness the unveiling of Octavius' latest venture, an elaborate fusion experiment undertaken with the hopes of providing an infinite supply of cheap energy for everyone. However, the demonstration turns into a disaster when the technology backfires on Octavius, killing his wife and causing four large impenetrable mechanical arms to be permanently attached to his body. The artificial intelligence used to operate the arms soon take over Octavius' own mind, turning him from a philanthropic visionary into an evil and powerful supervillain.
And of course, Spider-Man is there to take on the man dubbed "Doctor Octopus" by the local paper. Octavius disappears from sight after his fateful experiment, but he passes the time in hiding by assembling the machinery and technology to rebuild the same fusion device, this time much bigger. There is still one piece missing, though, and Octavius can only get it from Oscorp, and specifically, Harry Osborn. Harry may be physically threatened when Octavius climbs up the side of a building to Harry's penthouse to confront him, but since Spider-Man is still on the loose, Harry is willing to make a deal with Octavius: bring him Spider-Man, he'll give him whatever he needs. The first step is to find Peter Parker, who takes the webslinger's pictures.
"Doc Ock" does find Parker together with Mary Jane Watson (Kirsten Dunst), and Octavius takes M.J. hostage, telling Parker to deliver Spider-Man or else. When Spidey does arrive, he and Ock rumble throughout the city. Octavius puts all kinds of civilians at risk, especially a subway car full of people. Spidey miraculously saves them, but at great physical expense. Octavius easily captures him and takes him to Harry. Once Spider-Man is delivered to Harry, Octavius runs off with his winnings. In the meantime, Harry discovers the incredible truth about Spider-Man's true identity: he is Peter Parker, his best friend.
Soon enough, Spider-Man is back on his feet, off to battle Octavius. In an abandoned building, the doctor has his new fusion experiment in high gear when Spidey arrives. Octavius is intent on developing the means to generate incredible power, but Spider-Man is trying to prevent the city from being destroyed should that power become unstable, as it did in Octavius' original experiment. Another battle begins, and Spider-Man finds a way to electrocute Octavius, disrupting the AI's control over the scientist and allowing the good doctor to return to his senses. Octavius realizes the mechanical arms have been controlling him, and the only way to save the city from certain destruction - and to save his soul - is to collapse the entire building into the bay. Octavius caves in everything by using the arms to rip apart his experiment, and he sinks into the ocean with his creation. With the arms still attached to his body, one cannot be certain if the man will ever be separated from the machine.
INTELLIGENCE - 8: Octavius is a great scientist, and his brain was entirely at the disposal of the AI to build another powerful and destructive force.
POWER - 9: His mechanical arms are impervious to just about everything, and boy can they move fast to Octavius' commands.
VILENESS - 8: What's worse than dangling poor old Aunt May from the rooftops? Not a whole lot.
SWAY - 7: He is especially vicious and focused, especially while trading barbs with Spider-Man in the midst of endangering numerous civilians.
PURITY - 5: The AI running the mechanical arms did enough to put the city in great danger, but Octavius was finally able to overcome it.
PHYSICAL - 9: The arms just about cover up the fact Octavius is a chubby older scientist.