Doctor Octopus' mechanical arms were four metallic arms and they were Dock Ock's greatest weapons.
Otto Octavius created his mechanical arms to handle radioactive material. However, when his cold fusion battery exploded the heat from the explosion welded Octavius' metallic arms to his spine. As Doctor Octopus, Octavius used the four metallic arms as weapons. The metallic arms were capable of lifting a large amount of weight. The claws on the tip of the arms could grab objects and release sleeping gas.
In an alternate reality after Spider-Man's final battle with Doctor Octopus, Spider-Man removed the metallic arms from Doctor Octopus' spine and put them on his own body and began using them himself.
On Earth-92131, Doctor Octopus designed the claws with a more rectangular look.
On Earth-11983, Doctor Octopus designed his mechanical arms to where the claws were rounded and pointed at the tip.
- In Doctor Octopus: Armed and Dangerous, Doctor Octopus states that his mechanical arms are unbreakable. However, in Battle of the Insidious Six, Scorpion sprays acid from his tail and when it hits one of Ock's metallic arms the acid melts it, and in Make a Wish, Spider-Man uses the Argon Matrix Laser to cut through Doctor Octopus' mechanical arms.