The Insidious Six was formed by the Kingpin, who broke Chameleon, Scorpion, Mysterio, Shocker, Rhino and Doctor Octopus out of prison, for the sole purpose of destroying Spider-Man. At the time, Spider-Man was suffering from a mutation disease which initially caused him to partially lose his powers, allowing the Six to easily overpower him in a battle. They unmasked him, but wrongly concluded that Peter Parker wasn't in fact Spider-Man because of his poor performance against them.
The Insidious Six's failure caused Silvermane to wage war on the Kingpin's criminal empire, but the Six stopped him. However, Spider-Man, having partially regained his powers, saved Silvermane (unaware of his criminal activities). The Six's defeat led to their disbandment.
Months later, the Kingpin rallied the Insidious Six once again, this time to help him acquire the keys of the Six American Warriors that activates the Doomsday Device. As Mysterio had been killed since their last battle, he was replaced by the Vulture. With the Kingpin participating in most of their missions and coordinating their actions, the Insidious Six succeeded. They managed to collect the keys, and they defeated Spider-Man and the American Six. However, as the Six unlocked the door to the Doomsday complex, Chameleon released a sleeping gas knocking out his teammates and the captured heroes, betraying them to the Red Skull, his step-father, as his allegiance belonged to him and not to the Kingpin. The Red Skull was freed from his prison (a vortex) by the Chameleon and Rheinholt Kragov, the Red Skull's son. Later, Captain America emerged from the vortex and, in the ensuing battle, a part of the complex collapsed along with the Kingpin's ambitions for world domination. The rest of the Six disbanded once they realized that there was no profit to be made.
- Most other versions of the team are called the "Sinister Six", but Fox Kids censors felt that the word "Sinister" sounded too menacing for Spider-Man: The Animated Series (even though another Fox Kids children's cartoon at the time, X-Men: The Animated Series, included Mister Sinister as a villain).
If the series had continued for a few more episodes, the Insidious Six would have reformed.
- 8 Insidious Six (Earth-92131) Members
- 7 Appearances of Insidious Six (Earth-92131)
- Minor Appearances of Insidious Six (Earth-92131)
- Media Insidious Six (Earth-92131) was Mentioned in
- 4 Images that include Insidious Six (Earth-92131)
- Team Gallery: Insidious Six (Earth-92131)