Virtually the entire Marvel Universe was available to be used in this series. Though there were some exceptions as the show progressed as the Incredible Hulk and Ghost Rider set to have their own series on UPN.
By the time the Spider-man series came on, there was a lot of censorship at Fox and they were very nervous about violence. Fox had very strict rules about violence and language in the show, including: "When Spider-Man lands on the rooftop, be sure that he doesn't harm any pigeons."
When Peter gets the alien costume, and he's trying out the "outfit switching" ability, he has it turn him into "that guy from Aerosmith." This is a reference to Aerosmith guitarist Joe Perry, who performs the series theme music.
The entire X-Men team were going to be included in "Secret Wars", but ultimately had to be cut to one member because, according to writer John Semper, it would have been too expensive to get the cast to fly from Canada to Los Angeles to record their dialog for the show. However, Storm was the only one able to appear because Iona Morris was the only X-Men cast member based in California.
The creative team decided not to use Gwen Stacy in this series because they did not want to use a character that was dead in the comics for over 20 years and long time fans would expect her to eventually die. Because of this decision, many of the stories were changed to the events happening to Felicia Hardy or Mary Jane Watson.
Electro was supposed to appear in the series before his eventual debut in Season Five's "Six Forgotten Warriors" story arc. Electro was held back from appearing, however, because James Cameron tried for years to write and direct a theatrical "Spider-Man" movie with Sandman as the secondary villain and Electro as the main villain. The legal rights to the "Spider-Man" movie went into limbo for over a decade, with Electro and Sandman still intended to be the villains. However, writer John Semper was able to include him into the series, but not as Max Dillon and he was not an American. Instead, a new character was created for the show. On the animated series, Electro was really Rheinholt Schmidt, the second Red Skull who was the original Skull's son and the step-brother of the Chameleon, none of which was actually in the comics. Rheinholt's real last name was never revealed on the show, though he went by the assumed name of Rheinholt Kragov while the Chief of the Russian Police in the "Six Forgotten Warriors" episodes in season five, and the Red Skull later uses the Doomsday device to turn his own son into the ultimate weapon, Electro.
According to an on-line interview with John Semper, the reason that the Hobgoblin was added to the show in Season One before the Green Goblin was that plans for the character were being done before he arrived by writers and crew members that were no longer involved. By that time, the Hobgoblin had been made into an action figure for the animated series that was going to be released, so Semper admitted they had to let him stay on the series.
Radioactivity and all uses of the word were removed and replaced on this show with a science called neogenics, including the spider that bites Peter to give him his powers. Ironically, though, Joe Perry's theme music uses the lyric "radioactive spider blood."
Mary Jane Watson's character design is based on the artwork of John Romita. In the comics, Todd McFarlane had redesign the character because he thought she should look more contemporary. Her design in the comics revered back to the one by Romita.
John Semper mentioned that a rejected chapter for the "Secret Wars" story line was going to include the entire X-Men team, would have featured Mr. Sinister as the villain, and that Spider-Man would have actually bonded with a new black symbiote costume after his classic red-and-blue costume was torn to shreds. The episode was written, according to Semper, but never used because it would have cost too much to get the entire cast of voice actors from X-Men (1992) to appear again.
John Semper admitted in an on-line interview that a storyline with Dormammu and Mysterio was originally planned. However, plans for this were scrapped when the voice of Mysterio, Gregg Berger, had left the series.
John Semper, the story editor/producer for "Spider-Man: The Animated Series", revealed in an online interview that Richard Fisk was going to return if the show had been picked up for a sixth season. Semper said that Richard Fisk was going to become the crime lord known as the Rose, like he did in the Spider-Man comic books, and was going to try to frame Daily Bugle reporter Ned Leeds.
John Semper said in an online interview that a proposed sixth season would have had Norman Osborn, the original Green Goblin, return from limbo and take over the role of the Green Goblin from his son Harry. However, Fox Kids did not order another season and instead created Spider-Man Unlimited (1999).
The Incredible Hulk/Dr. Bruce Banner was actually supposed to appear on the 3-part "Secret Wars" storyline in Season 5. However, the Hulk was unable to appear on the series in Seasons 4 and 5 because the The Incredible Hulk (1996) was going tor air on rival network, UPN. As a result of the Hulk, and all related characters, being unavailable to the crew, the Lizard was written in the Hulk's place in the three "Secret Wars" episodes to make the story more "Spider-Man centric" than the "Secret Wars" comic mini-series.
The villain Puma was supposed to appear on the show. Story editor John Semper mentioned in an online interview the character was not used because they had simply ran out of new episodes to produce for "Spider-Man".
Story editor/producer John Semper said in an online interview that the Fox Kids network did not allow Spider-Man to punch anyone because other countries, such as Canada, were banning Fox Kids shows that featured fantasy violence like Mighty Morphin Power Rangers (1993) and Batman: The Animated Series (1992). This is why no one is ever punched in the gut or punched on the face on this series. Semper admitted he got lots of fan mail from confused viewers wondering why Spider-Man never threw a punch at his enemies.
While the X-Men, Iron Man and the Fantastic Four would appear on the show as guest heroes at different points in the series, John Semper confirmed in an online interview that Spider-Man was forbidden from appearing on the other super hero series on the Fox Kids network, as well as UPN's The Incredible Hulk (1996) later on. However, Spider-Man's hand can be seen shooting a web in part five of the Phoenix saga in season two of X-Men (1992) and an in-the-shadows Spider-Man can be seen in Bruce Banner's mind during a season two episode of The Incredible Hulk (1996).
The "Neogenic Nightmare" saga in Season 2 was as a direct rebellion against the restrictions from Fox as it features Morbius, a character that would irritate the censors. Also in this series, Peter's transformation was not caused by his attempts to remove his powers, but a result of his body mutating further from the original spider-bite.
The Sandman, was supposed to appear in the cartoon series, but was held back from appearing because James Cameron tried for years to write and direct a theatrical "Spider-Man" movie with Sandman and Electro as the villains. However, the legal rights to the movie went into limbo for over a decade and the character is the only major classic Spider-Man villain to have never appeared on the series.
Martin Landau was the original voice for Mac Gargan, a.k.a. the villain Scorpion. However, after he recorded dialog for the three episodes featuring the Scorpion in the show's second season, Landau had won a Best Supporting Actor Oscar for Ed Wood (1994) and was not able to do voice-over acting work anymore. He was replaced by Richard Moll, who provided the voice for the Scorpion in seasons four and five.
Neil Ross, who provided the voice for Norman Osborn/the first Green Goblin, is the only voice actor to date to voice the same character on two different Spider-Man cartoon series. Ross had previously done the voice of Norman Osborn, but not the Green Goblin, on Spider-Man and His Amazing Friends (1981).
The crime lord the Owl appears in the first chapter of season two's "Neogenic Nightmare" saga, Spider-Man: Neogenic Nightmare Chapter 1: The Insidious Six (1995). He is seated with other crime lords, including Hammerhead and Silvermane, during a meeting with the Kingpin. Though the Owl never speaks in the episode, this is the first and, to date, only time the Owl has ever appeared on a Spider-Man animated series.
This series was originally going to have Norman Osborn become the Hobgoblin because, due to a decision made by crew members who ultimately left the "Spider-Man" show, the Hobgoblin was going to make his debut before the Green Goblin. However, Spider-Man's co-creator Stan Lee, rejected the idea of Norman becoming the Hobgoblin and Norman would instead create the Goblin equipment for the Hobgoblin.
In an online interview, John Semper felt that Carnage should have appeared more on the series because there was so much more potential for him story wise. However, he didn't feel he needed any more episodes devoted to Venom because he felt the character was "starting to show his age" during his two episodes in season three and didn't want to use the character anymore.
Betty Brant was supposed to appear on the "Spider-Man" animated series. Instead of being J. Jonah Jameson's secretary, Betty was supposed to be the assistant of Joe "Robbie" Robertson and fond of Peter Parker. While a model sheet of the character was drawn for the show, the writers did not get the chance to use Betty because they had ran out of new episodes.
Kathy Garver, the voice of Firestar on Spider-Man and His Amazing Friends (1981), will appear on several episodes of "Spider-Man". She does the voice for the lizard woman Gila in season four's "The Lizard King" episode and the voice of Madeline Joyce/Miss America in the five-part "Six Forgotten Warriors" storyarc.
In the comics, Herbert Landon only appeared in "The Mutant Agenda" mini-series comic which was also adapted into a two-part episode. However, Landon was used quite frequently on the show after his initial appearance taking the place of Alistair Smythe as the Kingpin's scientific confidant. Also after his initial appearance, the left half of Landon's body remained mutated.
Despite the show being based in the Marvel Universe, there are a few subtle nods to DC universe characters. In Spider-Man: Sins of the Fathers Chapter 2: Make a Wish (1996), the young girl asks Spiderman how he got his powers, saying that a friend thought he was "from a dying planet, and his parents sent him here on a little spaceship" and spiderman replies that her friend has him confused with someone else. This is a nod to Superman's origin. Also in the episode that showcases Tombstone's origin, when Spiderman rescues Tombstone from falling into the chemical vat again, he comments that if he fell in his hair "might turn green". This is a nod to the origin of DC villain The Joker
Peter Parker's character design was originally intended to resemble the one seen in the comics. However, the design was switched towards the final production of the show after Stan Lee wanted Peter Parker to look more contemporary. Stan Lee described how how he wanted Peter Parker to look and Bob Richardson drew what Stan was describing to him.
During the middle of the 5th season of Spider-Man, Fox Kids was thinking about keeping the series on a little longer but then Marvel and Fox Kids decided to ended after 5 seasons and show a 2-hour series finale. The reason why Fox Kids and Marvel canceled the show had nothing to do with ratings. The reason was the fact that Saban Entertainment wanted to Marvel's animation for their cartoon series. So after the series was cancelled, Marvel and Saban made another completely unrelated Spider-Man series called Spider-Man Unlimited (1999).
Supervising Producer Bob Richardson said that of all the show's seasons, season five was the most problematic. The mistakes in those episodes, as well as the animation's poor quality and overtly-repeated scenes for season five, were a result in a three-month delay in writing the season five scripts. When the scripts did finally arrive, most of which were written by John Semper, the season five stories were the most complex scripts the "Spider-Man" animated series had. Richardson said the season five scripts "went against everything we were trying to do in an effort to keep the workload on all of the production at a reasonable level", due to the new characters, locations and guest hero and villain powers included. Semper wrote most of the stories in season five himself due to several writers, including Brooks Wachtel and Stan Berkowitz, leaving the series during the three-month delay for season five.
After Season 1 wrapped up, Peter Parker changed his wardrobe by switching his green, white and blue shirt for a brown or pastel pink t-shirt and grey jacket and his brown casual shoes for white sport shoes and continue to have this look for the rest of the series.The creative crew said they ended up revising Peter's wardrobe in Season 2 to make it better than the design they started with and give Peter a cooler look, as well as better hide his Spider-Man costume under his clothes.
In the comics, the Insidious Six are called the Sinister Six. The Fox Kids network had the name changed to "Insidious Six" because they thought the name "Sinister Six" sounded too menacing for a cartoon series for children. Only two of the members of the team from the comics make it into the team's roster: Doctor Octopus and Mysterio. Shocker, Chameleon, Scorpion and The Rhino are the remaining four on the original animated team, while Sandman, Electro, Kraven the Hunter, and The Vulture were the remaining four on the original comic team. Both teams had an original member replaced (The Vulture who joins the Six to take Mysterio's place in Season 5 while Hobgoblin joins the Six to take Kraven's place in the comics)
Story editor/producer John Semper said in an online interview that the villain the Beetle was supposed to appear on "Spider-Man: The Animated Series". Semper said he had meant to include the Beetle in an episode of the animated series, but he simply never got around to using the character.
Story editor/producer John Semper said in an online interview that three of the Fantastic Four characters were given new voice actors for the "Secret Wars" three-part story line because he did not like the Fantastic Four (1994) animated series that ran on the Fox Kids network. The only cast member to reprise his role from "The Fantastic Four" on "Spider-Man" was Quinton Flynn, who returned as the voice actor of Johnny Storm/the Human Torch.
Harry Osborn makes his first animated appearance in this series. Though he never appeared in any prior Marvel shows, Harry was mentioned as Peter Parker's friend and roommate in 1981's "Spider-Man" animated series.
Eric Braeden was originally supposed to be the voice actor for the character Herbert Landon. However, Braeden was uncomfortable with voice acting and story editor John Semper said Braeden gave "a very wooden performance" as Landon. David Warner ultimately took the role as Landon.
The trivia items below may give away important plot points.
A sixth season was planned for "Spider-Man" which would have had Spider-Man find the real Mary Jane Watson from limbo with the help of Madame Web. Story editor John Semper said in an online interview that it purposefully left unresolved to see Spider-Man find the real Mary Jane because the crew thought they were going to get another season or two of "Spider-Man". However, Margaret Loesch, who was the president of Fox Kids network at that time, hated one of the show's executive producers, Avi Arad, due to the fights they'd usually have over the show and she wanted to put Arad out of business. When the sixty-five episode contract for "Spider-Man" was up, Loesch decided to cancel the show and had permanently shut down Marvel Films Animation, the company that provided the animation for Spider-Man. Loesch and the Fox Kids network had a better relationship with Saban Entertainment, who wanted to do animation for other series for Fox Kids, including ones for Marvel. Instead of continuing "Spider-Man", the Fox Kids network decided to go with a new, completely unrelated series "Spider-Man Unlimited".
A mini-series was actually supposed to take place after the series finale, in which Spider-Man journeys with Madame Web backwards through time to find the missing Mary Jane Watson. He would have ultimately found her in Victorian England with amnesia and she would have been hunted by Carnage, who was also trapped in that time period and was impersonating Jack the Ripper. Once Spider-Man had stopped Carnage and had left with Madame Web and Mary Jane back to the present, Mary Jane would have regained her memory and ultimately admitted to Spider-Man that she had always known he was Peter Parker, which had been hinted at throughout several episodes of the animated series.
Ghost Rider was scheduled to appear some time in the fifth season of the show. In the story, written by John Semper, it would have been revealed that Mysterio was alive after his off-screen demise in season four's Spider-Man: Partners in Danger Chapter 9: The Haunting of Mary Jane (1997), and he would have used a Time Dialation Accelerator device to commit a series of robberies. Mysterio would have been discovered by Baron Mordo, who wanted Mysterio to use the Time Dialation device to free his master, Dormammu, from another dimension. Spider-Man would have teamed-up with Ghost Rider to stop their plans from bringing Dormammu out of his dimension, though it is not known what the fate is of the Time Dialation Accelerator or how there was a new one since the previous was destroyed on-screen in Spider-Man: Sins of the Fathers Chapter 14: The Turning Point (1996), when the Green Goblin is banished to limbo. However, Marvel was trying to get a "Ghost Rider" animated series done on the UPN network at the time and the Fox Kids network did not want to give exposure to a character who would have appeared on a rival network. According to Semper, the Ghost Rider episode was actually written but never used, and the "Ghost Rider" series for UPN ultimately was rejected. Ghost Rider did, however, appear as a guest star on The Incredible Hulk (1996).
Peter Parker/Spider-Man was actually supposed to marry Mary Jane Watson in the series finale, but story editor John Semper rejected the idea and instead had Peter marry Mary Jane in Spider-Man: The Wedding (1997). Semper was against the two being married for real because he felt Peter Parker should "never get the girl" on the animated series.