Mays Billy began to increase the number of trolls under his command in 2014, foreseeing that the Form Wars would leave our universe vulnerable to attack. In 2015, Fari killed King Harkinian, one of the only two people who could wipe out the trolls and prevent them from reaching Earth. Fari then established contact with United 'Gees Universe by opening a portal between our universe and the rest of the multiverse. Unknown to anyone at the time, this allowed trolls to leave their home in Velsoje Die and visit other universes. Even worse, the other being who could wipe out the trolls, Mama Luigi, was killed during the final battle of the Form Wars in 2018.
Mays Billy finally left the Velsoje Die universe and entered our universe in January 2019, about a year after the Form Wars ended, and brought tens of millions of his troll servants with him. Their goal was to destroy YouTube Poop and everything related to it, including the entire universe. Researchers at Patrick Star Wumbology College soon detected the newly-arrived horde and alerted the government of Hyrule. Link doubted the reports, but the resurrected cyborg version of King Harkinian, a longtime supporter of wumbology, convinced him to launch efforts to build up Hyrule's defenses. Many other countries received similar warnings, but only a few, such as the Koopa Kingdom, took them seriously.
When Mays Billy's space trolls first entered our universe, they were small, but the matter of the universe allowed them to grow huge and dangerous. They reached Earth, but were repelled after over a month of fierce fighting thanks to the efforts of Chuck Norris, Impa, Gaston, and others. However, another group went to Plit and managed to destroy most of the Mushroom Kingdom, killing Mario in the process, and Princess Toadstool fled to the Koopa Kingdom. They also destroyed much of Gamelon and Koridon, and they overran all of Gannonan and re-killed Ganon. Other trolls assaulted Truceland and massacred much of its already-tiny population of forms, and Earth suffered an even more brutal assault that threatened to overwhelm even Chuck Norris. By May 2019, things seemed hopeless.
Things Turn Around
By June 2019, the Koopa Kingdom had managed to ward off the trolls and develop a peace treaty with what remained of the Mushroom Kingdom. Meanwhile, Gwonam, Squad Allah, and Morshu helped fend back the trolls using bombs and urine, keeping them away from Koridai and Gamelai, while Link and Zelda fought to stop the trolls from destroying Gomalan. Fortran even joined the struggle to prevent Earth's destruction, as it contained his favorite place in the universe. Also, Secret Weapon Luigi led a coup against Brooklyn Mario and seized control of Truceland, then led its few remaining forms in a desperate stand against the trolls.
However, Morshu, Gwonam, Gay Luigi, and Secret Weapon Luigi were all killed during the invasion, and then I.M. Meen, the chosen one, finally faced Mays Billy in battle. They had a big fight, and with a little help from Cyborg Harkinian and a revived Mario, Meen was able to destroy Mays Billy and his trolls. With that, the Poopocalypse had ended, leaving the universe at peace and harmony.
The invasion had devastating effects on Hyrule and the Mushroom Kingdom. Princess Toadstool was deposed and murdered in favor of President Luigi J. Video. Many YTP characters were killed during the Poopocalypse, and as new sources kept opening up to poopers, the variety and richness of poop allowed it to become a business making movies and TV. A game was also made based off it.