Battle For The NeverhoodDr. Kogg creates a gas that causes people who inhale it mutated into monsters and obey Kogg. He then sprays it all over the Neverhood, which results nearly every chao turning into monsters. However, Klaymen and some of his friends were immune to the gas and they go on a quest to save the island and defeat Dr. Kogg.
When Kogg realized the Chao Gang were immune to his formula, he orders his mutant slaves and lurker monkeys to kill them. But, the chao gang manage to defeat the monsters and saved their closest friends. Kogg, furious about this, goes into his secret Forteress with the Chao Gang in close persuit. Kogg fights the Chao Gang by mutating himself with his own formula, but gets defeated. Before Kogg can finish off Klaymen, all of his friends show up and Kogg flees as the island explodes.