Baron Mordo (voiced by Tony Jay) first appears in the episode "Sins of the Fathers Chapter 1: Dr. Strange". In the show, Mordo appears as Dormammu's minion. In his first appearance, he was ordered by Dormammu to steal the Wand of Watoomb to make a portal that would release him from his dimension. To do so, Mordo brainwashes Mary Jane Watson to become his servant by passing himself off as her long-lost father. His plan almost succeeded, but Spider-Man, Doctor Strange, his assistant Wong, and Mary Jane stopped him from freeing Mordo's master from his dimension. Mordo's origin is also revealed in this episode where he was once a student under the mystic figure known as the Ancient One's teachings. But when Mordo tried to kill the One, which was discovered by Strange who attempted to stop Mordo but Mordo in turn had stopped Strange, the Ancient One foils Mordo's assassination attempt and expels him, revealing that he had known about Mordo's plan all along.

Later in "Venom Returns" and "Carnage", Mordo was ordered by Dormammu to bring the Venom symbiote back to Earth to make Eddie Brock whole once more. Then, Dormammu orders Mordo to give Brock a message. At Stark Enterprises, Mordo disguises himself as Orden Bloom to get the portal. When Spider-Man and War Machine join forces to fight Venom, Dormammu tells Mordo that there is another symbiote, which Mordo then bestows to Cletus Kasady, naming the result into the evil "Carnage".

After retrieving the probe, Dormammu orders Carnage to steal the "life force" energy from humans, so he may gain enough strength to enter our world. When Carnage absorbs too much force, Mordo brings him back to his lair to drain the power into an urn. When Carnage moves to send the urn into Dormammu's portal, Spider-Man, Iron Man, and Venom interrupt. Mordo ordered Carnage to throw the urn to unleash Dormammu, but was thwarted. Sacrificing himself, Venom pulled Carnage into the dimension following Dormammu's reversion, after which Mordo made his escape.
The Big Wheel (voiced by Michael Des Barres) appeared in episode named "Rocket Racer"; his real name is Jackson Weele. Weele is the head of a band of high-tech thieves, whose technology is stolen by the Rocket Racer, so Weele goes after Rocket Racer. It takes the combined power of Spider-Man and the Rocket Racer to stop the Big Wheel and put him behind bars.
The creation of Carnage was orchestrated by Dormammu. The Venom symbiote had previously been launched into space aboard a probe by Spider-Man, but, learning that it was on the verge of asexually reproducing, Dormammu had Baron Mordo bring the probe back to Earth. When the recently arrested Cletus Kasady (voiced by Scott Cleverdon) witnessed Brock's reunion with his symbiote, he was soon offered the chance to merge with the symbiote's spawn. Becoming Carnage, he was sent out to capture enough "life energy" from human beings to provide Dormammu the strength to enter our world. Because of the degree of censorship placed on the show, this version of Carnage was quite noticeably tamer and less violent than his appearances in the comics, merely draining life from his victims, which was later restored, rather than killing them outright. He was eventually defeated by Spider-Man, Iron Man, and Venom, as he, Venom and Dormammu were sent hurling through a dimensional vortex.

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The Beyonder (voiced by Earl Boen) in the cartoon greatly differs from the comics, as he sports a goatee as opposed to having a clean-shaven face. In all his appearances he also wore the brief "super hero" costume from Secret Wars II instead of the more usual disco outfit. He is also actually more of a good guy than a villain. The Beyonder first appeared in the episode "Arrival" of Season 5, the first chapter of that "Secret Wars" in the series. The Beyonder worked with Madame Web to prepare Spider-Man for the Secret Wars. When Doctor Doom was defeated in "Doom" (the third and last chapter to the "Secret Wars") after the villain temporarily stole the Beyonder's powers, the Beyonder had all the heroes Spider-Man had summoned to assist him forget their actions, and sent them home.

Spider-Man, however, was needed for something bigger, so he was the only one whose memory was untouched. It was revealed that the evil Spider-Carnage had destroyed the entire multiverse with a giant bomb. However, when the destruction reached the Beyonder's own reality, he used all of his powers to roll back time. Though it tested him to the extreme, he sent his servant, Madame Web, into the past to train Spider-Men from many different realities to find out which one would be worthy enough to lead the others against Spider-Carnage. In the series finale, he was growing weak because he had stayed too long out of his own reality, but had managed to find enough strength to teleport the six-armed Spider-Man, who had mutated into a Man-Spider, away back into another reality with him.
Bruce is a stone gargoyle on top of a building whom Spidey talks to whenever he doubts himself. It is often thought that he got his name from Bruce Wayne aka Batman. This is due to the fact that sometimes, Spider-Man mocks Bruce. However, John Semper revealed in an interview that Bruce was named after his good friend, Bruce Helper.
Billy Connors (voiced by Toby Scott Ganger) is the son of Margeret Connors and Dr. Curt Connors. He only appeared in the series premiere "Night of the Lizard".
Margaret Connors (voiced by Giselle Loren) is the wife of Dr. Curt Connors. She first appeared in the show's very first episode, "Night of the Lizard" and her last notable appearance was in "The Lizard King". Throughout most of her appearances, Margaret has been involved in one way or another in changing her husband, Curt, back into his human form from being the Lizard.
Calypso (voiced by Susan Beaubian) was initially introduced as a research scientist named Dr. Mariah Crawford, who was engaged to Sergei Kravinoff before his mystic serum transformed him into Kraven the Hunter. She assisted Spider-Man in several episodes

In "The Return of Kraven", Crawford was given the serum herself by Kravinoff when she fell ill from an African plague that she was help fighting. This transformed her into a feral woman who greatly resembled the comic version of Calypso except for having a lioness-like face and ears, different colored eyes, and claws. She was eventually half-cured by Spider-Man, Black Cat, and Kraven the Hunter and she refused to be cured all the way back to Dr. Mariah Crawford, running away with Kraven with the both of them with unknown fates.

During her appearances, she was called Calypso by Kravinoff even before sh…

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