Dr Otto Octavius, also known as Doctor Octopus, is the secondary antagonist of Spider-Man: The Animated Series.
He was voiced by the late Efrem Zimbalist Jr.
Otto Octavius helped run a science summer camp where Octavius helped mentor Peter, who was like him and smart but picked on by the other children. Otto was desperate to finish his experiment. He took on the name Doctor Octopus.
He went to the Hardy estate to kidnap Felicia, who happened to be going out on a date with Peter. However, Octopus spoke to Peter. Remembering him from the days of science camp, Octopus agreed to let Peter deliver the money. Peter arrived and Octopus revealed his plans Peter became horrified. He threw Peter out. Spider-Man then arrived and fought him. He then trapped Octopus again and quickly saved the two hostages. Octopus was sent to prison where he later was broken out along with Mysterio, Chameleon, Scorpion, Shocker, and Rhino. They formed the Insidious Six under command of the Kingpin. They fought Spider-Man and beat him. Unmasking him, they found he was Peter. However, Octopus theorized that Spider-Man's poor performance meant that Peter was not really him. They captured Peter and Octopus faked being a medical doctor to fool his Aunt May.
Peter led him to the real Spider-Man where he appeared and defeated them all. He found Spider-Man without any memory. He convinced the hero that he was Octopus' partner. However, a taxi driver and a terminally ill girl helped him get his memory back. Spider-Man then defeated him again. Octopus later kidnap Cat from S.H.I.E.L.D. They forced Cat to redevelop the super soldier serum that created Captain America. Octopus once again joined the Insidious Six under the Kingpin. Their plan was to find the doomsday device developed by Red Skull during World War II. They traveled to Russia where Chameleon betrayed them, revealing himself to be Red Skull's son.
Octopus was one of the supervillains chosen by the Beyonder for the Secret Wars. He was defeated by the superheroes. He was sent back to Earth with no memory of what happened.