He built an artificial environment in his barn, then began to gather insects of all types, from near and far. In his own words, John's reason for doing this was: "As man evolved from apes, so too must insects evolve from their present, passive state--to a larger, more aggressive, mutant stage where they will be capable of taking from humanity their fair share of Earth's bounty! After, of course, they have secured for me my revenge against those who laughed at me and called me mad! And from this day forth, mankind will tremble in fear at the name...Odd John!"
(Micronauts#19) - Not too longer after this, a group of adventurers from the extradimensional Microverse arrived on Earth. One of these, an Insectovorid known as Bug, scouted out their environment, only to be discovered by Odd John. Despite taking a blast from the miniature warrior's rocket-lance on the hand, Odd John subdued Bug with his gas and then exposed him to his mutagen gas.
Soon enough, Bug's teammates came looking for them in their ship, the Endeavor. When the ship proved resistant to his gas, John smashed it with a pitchfork. When Rann and Acroyear engaged John, he grabbed a shotgun and blasted the ship. After being blasted a few times by the flying warrior, he released the newly mutated Bug and other insects. Bug blasted Acroyear into unconsciousness, while John gassed Rann. After checking out the micro-warriors and deciding they weren't insects, John decided to just preserve them, by skewering them on the board next to his butterfly collection. He also sent his swarm of mutated insects to start their war on humanity.
As John's needle drew ever nearer to Rann's chest, a swarm of normal insects gathered the attention of Ant-Man, who flew off to the rescue aboard his trusty steeds, Blixen and Vixen.
(Micronauts#20) - Another of the micro-warriors, Mari, having regained her bearing after being knocked out in the attack on the Endeavor, leapt from a height and catapulted a hammer across the room, smashing into Odd John's head and knocking him out. By the time John had regained consciousness, Rann and Mari had bound him in chains, and they told him that they would stop his insect army and restore their ally. He revealed that when he had fallen to the ground, he had smashed his control device and that the insects could not be called back.
Correctly figuring that the insects would respond to their instinct for food, the Micronauts located the swarm approaching a nearby Food World™. Joining together with Ant-Man, who arrived on the scene just a few minutes before them, they fought the swarm, eventually discovering that Ant-Man's Pym Particles not only would shrink the giant insects, it also reversed their mutation almost instantly. The process proved effective on all of the insects, and on Bug as well, and the threat was eliminated. Ant-Man then followed the Micronauts back to Odd John's farm, where he saw to it that John was arrested, and his lab dismantled.
Sadly though, Vixen, one of Ant-Man's ants was slain by one of Bug's blasts.