The gigantic monsters known as "Fatal Fluffies" are the true gods of the Earth. Having slumbered underground for millennia, these ancient beasts have finally have finally returned to reclaim the surface from the invaders who have long infested the planet!
According to Crystal Ball, the Fatal Fluffies were the Earth's antibodies and they were beginning to awaken in response to all the various alien races that had begun to invade the Earth. Believing he could control them, Crystal Ball built an army of followers in Inner Mongolia with promises that he could protect them from the monsters. The first Fatal Fluffy to truly awaken revealed itself in Hohhot, emerging from the ground briefly before grabbing the Dreadnoks and returning to its subterranean dwelling to G.I. Joe's shock and Crystal Ball's delight.
After another Fatal Fluffy emerged from the bottom of the Indian Ocean, G.I. Joe dispatched Skywarp to keep the monster busy while Stretcher, Deep Six, and Shipwreck attempted to bio-scan the beast so they could learn more about it. After Skywarp grew tired of wrestling with the beast and broke one of its horns off, the Fluffy knocked the Cybertronian down and swam away. Though their scans were incomplete, the horn Skywarp broke off still gave the Joes enough information to begin developing a way to track the Fluffies. Soon after, another Fluffy emerged from Mount Cotopaxi in Ecuador. Though the combined firepower of Cover Girl's Wolverine and Skywarp weren't enough to put the monster down, Salvo managed to drive it back into the volcano with a pair of BFGs.
- Fatal Fluffies originate from the 80s G.I. Joe animated miniseries "The Pyramid of Darkness". There, they were genetically engineered by Cobra and transformed into their Minotaur-like appearance from a smaller, Mogwai-esque form. The original Fluffies were also smaller, towering over most humans but nowhere near as big as the Cybertronian scaled ones that have appeared in IDW.
- Thus far, the Fatal Fluffies have gone unnamed in-universe but were referred to as such in the opening of G.I. Joe vol. 5 #4's letters column.
- The role of the Fatal Fluffies in the story was originally supposed to be held by the other big scary underground monsters from an 80s Hasbro cartoon, the Inhumanoids, but after the script outlines had already been approved it was discovered that Hasbro no longer had the rights to the Inhumanoids name or characters, prompting a quick-and-dirty swap-out. The Fluffy that attacked the Dreadnoks was supposed to be the plant-monster Tendril; the one that transformed Rock 'n Roll into a monster was to be the corrupting D'Compose; the eggs in the nest were to hatch into multiples of reptilian Inhumanoid Sslither; and the "progenitors" in the climax were substituted for Inhumanoid leader Metlar. 
- G.I. Joe #5 script by Aubrey Sitterson on Patreon