For Christmas Jack has received a chemistry set and he decides that he is going to create the perfect insecticide in order to get rid of the roaches once and for all. But instead of getting rid of them, they start multiplying infinitely!Official Synopsis, 
Cloning Around is the 67th episode of Season 1, and was remade as the seventh episode for Season 6 under the title The Great Invasion. Jack accidentally invents a gas that clones whoever it's used on.
During Christmas, Oggy and Jack are opening up their presents. Jack receives a new science kit, to his excitement while Oggy receives a new canister of insecticide and was given a box of chocolates. Dee Dee, however, immediately steals the box, prompting a chase, ending with Joey slamming a pillow on Oggy and Jack. The Cockroaches manage to win, causing Jack to try out the new insecticide. Unfortunately the insecticide proves to be a dud, as the roaches were shown dancing around the fog.
Jack, having enough of the Cockroaches, decides to experiment with his new science equipment to make a more useful, deadly version of the insecticide. Oggy hears his cousin laughing menacingly as Jack hits him while opening the door. The door was closed and Oggy falls down. Oggy gets up afterwards. At the kitchen, Jack uses Joey, who is eating a pickle, as the guinea pig for his new spray. To his horror, Joey sprouts a large tumor from his body which eventually separates and creates an identical copy of himself. Jack then sprays on Joey again, but it creates two more Joeys. The multiple Joeys, along with Marky and Dee Dee begin to chase him, as Oggy watches them. Then, as the cloned cockroaches beat up Jack, Oggy uses the spray on them again, unaware of the effects, but Jack warns his cousin to not spray on him. This causes an even larger army of Cockroaches to sprout. Oggy runs away in terror, dropping the spray by mistake which one of the Joeys takes.
In the kitchen, the multiple cloned roaches abuse the spray to steal food. The cousins formulates a new plan. The Cockroaches happily indulge themselves with the contents of the fridge until they notice Oggy and Jack, wearing raincoats, properly prepared to stop the army of clones. This results in a massive curb-stomp battle ending in the cats' favor. However, there is one last Joey that needs to be caught, who steals the cloning spray and rapidly fires it at the captured cockroaches.
This results in the house being flooded with cloned roaches. As they evilly laugh away, they once again notice something: the cloning spray has affected the cousins as well, creating an even larger army of Oggys and Jacks. The cloned cats begin to beat up the Cockroaches, now finally having the upper hand.
- ↑ Oggy and the Cockroaches - The Great Invasion (S06E07) Full Episode in HD (published by OGGY on Jan 1, 2018, on YouTube. Accessed Sep 7, 2019.)