Being one of Spider-Man's most long-standing and popular villains, Doctor Otto Octavius also known as Doctor Octopus/Doc Ock would also battle the teenage Peter Parker in the Ultimate Spider-Man series, which takes place in a separate Marvel Universe. Under the pen of writer Brian Michael Bendis and artist Mark Bagley, the former scientist turned super-villain underwent a modern re-imagining who gave Peter more than a fair share of trouble. One of the more significant changes was to Ock's powers, originally just mental control of his metal tentacle arms, which put him in the same league as the popular X-Men icon/villain Magneto!
The original Otto Octavius was an intelligent yet stocky scientist who was injured during a lab accident when a radiation leak caused an explosion, which bonded an advanced four-armed mechanical harness that he used to safely handle dangerous chemicals to him mentally and physically. Taking an insulting nickname as his new identity, Doctor Octopus began a criminal career that brought Spider-Man into his cross-hairs and the two have been consistent nemeses to this day. In Ultimate Spider-Man #2 , Otto was a scientist at Oscorp who was injured in the same accident that turned Norman Osborn into the Green Goblin. Bonded to his nanobot metal arm harness which he would be able to upgrade and modify, Otto originally used his new powers to seek vengeance against entrepreneur Justin Hammer, whom Otto had been employed as a corporate spy, and was given his name jokingly by Spider-Man. After being defeated by Spider-Man, Doctor Octopus was remanded into SHIELD custody where he and four other Spider-Man villains eventually escaped together to form their version of the Sinister Six, which included a blackmailed Peter Parker.
After their defeat by the Ultimates, Ock's harness was removed from his body and stored in a separate facility where Otto revealed he maintained a mental connection with the arms, which eventually found and reunited with him. Getting the best of Spider-Man on the set of the Spider-Man movie, Otto later assaulted and humiliated the young Parker before getting defeated and returned to SHIELD custody. Realizing his mistake, Nick Fury punished the murderous Otto by having him watch as they melted his mechanical arms in front of him. Otto would return as the mastermind behind the 'Clone Saga' storyline, having created all the Peter Parker clones under FBI/CIA supervision. Having been drawn into a fight with the surviving clones, Otto revealed that his powers didn't end when SHIELD destroyed his arms but that the accident which empowered him gave him Ferrokinesis, the ability to manipulate all kinds of metal and magnetism, as he creates four makeshift arms from spare metal lying around.
Killing one or two clones almost to prove he hadn't lost his touch, Otto fights Spider-Man and Spider-Woman while mocking his shared history with Peter, his current lack of humor, and the kind of monologue his mainstream Marvel incarnation was fond of. During the battle, Ock admits that he didn't need to create the arms but that he got good at them, admitting to actually have enjoyed his time as Doctor Octopus. His self-realization ended with a combined punch from both spider-people and Otto was returned to SHIELD custody. Later appearances would continue to showcase Ock's control over metal as he constantly appeared with makeshift metal arms which he would use to battle his enemies.
In some ways, this change to the character's power set by Bendis makes the Ultimate Doctor Octopus possibly more dangerous than his mainstream counterpart. While the latter has years of experience and invention behind him, this younger, more muscular version has the ability to control all metal, with a preference for re-creating his signature arms. Considering the kind of danger Magneto and his powers has been to the X-Men for years, it's a shame that the Ultimate Doctor Octopus didn't get a chance to explore his powers fighting other heroes (or villains) in the Ultimate Marvel universe. But in the end, regardless of what universe Doctor Octopus is found in, all paths eventually lead to Spider-Man.