There have been two Doctors Octopus in the
Marvel Comics universe. The better known of the two, Dr. Otto Octavius, first appeared in Amazing
Spider-Man #3, written by Stan Lee with art by Steve Ditko.
Dr. Otto Octavius was a brilliant nuclear physicist who had invented a four-armed device that he used to manipulate radioactive elements. The arms telescoped to varying lengths and were incredibly strong. While demonstrating the arms, the experiment exploded, which bonded the arms to his body. He found that he had complete control over these arms, and used them to commit crimes. This brought him to the attention af Spider-Man, who put a stop to this sort of thing all the time.
Over the years, Doc Ock's plans have been everything from bank robbery to world domination. He retools his arms about every time he shows up to make them better, stronger and faster, but it never helps that much. He's the brains behind the Sinister Six, a group of villains devoted to killing Spider-Man. He's also responsible for the death of Arthur Stacy, Spider-Man's friend on the police force.
Over the years, his "brilliant but evil" persona changed into more of a "brilliant but paranoid and homicidal" persona. Still, he's had his mellower moments. Spidey's Aunt May almost married him once. In the mid-90's, he seemed to be happy in the company of an attractive superpowered woman named Stunner. He learned that Peter Parker was Spider-Man (which shouldn't have been too surprising, since Doc Ock beat and unmasked Spider-Man way back in Amazing Spider-Man #3). He had come to rely on the continuity of fighting Spider-Man, who was about to die from a "chemical virus" the Vulture infected him with. Otto couldn't let his long-time adversary and a good man die. So he created a cure, and Peter survived. And what did Otto get in return? Kaine snapped his neck.
That's right, we've entered the clone saga. Enter Doctor Octopus #2, a woman by the name of Carolyn Trainer, the daughter of Dr. Seward Trainer, another key figure in the clone saga. She first appeared in Amazing Spider-Man #406. Young Carolyn worked as a lab assistant to Dr. Octavius, because hey, even megalomaniacal scientists need a little help with their experiments. The experiments that she was helping him with involved virtual reality. Shortly before his death, Otto uploaded a simulcra of his consciousness into virtual reality (this is comics, they do just sort of have a virtual reality out there, like the internet, but cooler). This program/person went by the moniker of the Master Programmer, and helped keep Otto's criminal empire running smoothly while he was dead, but someone else needed to take up the tentacles.
Carolyn was more than happy to pick up the Octopus mantle, and even made a few improvements to the equipment. Her tentacles had lasers, and she wore some pretty tough body armor, including a ridiculous-looking helmet to protect her from "knockout punches". And did I mention the personal force field?
Her ultimate goal was to merge reality and virtual reality, which would allow the Master Programmer to be a real person, not to mention royally confuse the plot of The Matrix. It was during this storyline that we learned that Stunner was actually a VR construct given solid form; she was the creation of a lonely, overweight woman named Angelina Brancale, secretary to Carolyn Trainer. This construct was made possible using technology created by Dr. Octavius. Stunner loved Otto out of gratitude for being able to live life in a superpowered and attractive body. This explains how a short, glasses-wearing man with a mop-top could attract a woman who goes by "Stunner".
The whole virtual reality thing didn't pan out, thanks to some interference from the Scarlet Spider, and all Doc Ocks were out of the picture for a little bit. Then, the Rose, a crime boss, had the brilliant idea of raising Dr. Otto Octavius from the dead to help out with the crime business. Naturally, this attracted the interest of Carolyn Trainer and Stunner, who sat in on the dark ritual. It turns out that to bring Otto back, they needed to give him someone else's life essence. Spider-Man was originally tapped for this, but he escaped just before the ceremony was completed. Another life essence was needed, and Stunner volunteered. Here's where things became problematic: Stunner is not a real person. So when the guy running the occult ritual tried to use her life essence, she sort of dissolved. Angelina Brancale, hooked into all of her VR equipment, went into a coma. And Otto came back a little different. For one thing, he no longer remembered Spider-Man's secret identity. But more importantly, he was back to being an unstable, murderous mad scientist. Carolyn gave back her tentacles and went back to being his assistant, and Otto returned to his criminal ways.
The good doctor has recently been incarcerated, but that happens quite often, so I'm sure that he'll be back soon. And if the comics world isn't good enough for you, he's the villain in Spider-Man 2, so you can catch him in surround sound digital picture. Woo.