The 'WoW' plague that killed thousands of characters
September 13, 2005, was nearly the end of the World of Warcraft world as we know it. On that day, Blizzard released a patch designed to create more fun and adventure. Instead (as recapped by Gamepedia), it unleashed the biggest, deadliest, bloodiest plague in Azeroth's history.
The patch opened up a new area for players, called Zul'Gurub, which centered on a super-challenging raid designed for the best and strongest WoW players around. The final boss was an evil demonic dragon called Hakkar the Soulflayer who, even by evil demonic dragon standards, was a total jerk. To ward off any adventurer who might dare face him, Hakkar employed a devastating spell called "Corrupted Blood." It was exactly what it sounds like: Hakkar would corrupt your blood and cost you several hundred hit points every few seconds. If you were strong enough and had enough healing potions, you could survive the debuff and kill Hakkar anyway.
There was just one small problem: the debuff was contagious. That alone wouldn't be an issue, but thanks to an exploit in the patch, players with pets that caught Corrupted Blood began to inadvertently affect players outside of Zul'Gurub. If a player with an infected pet entered a busy area filled with other gamers, just about everybody nearby would contract Corrupted Blood. And with that, Azeroth was officially Plague Central.
Countless thousands of characters began to die, many immediately so because they weren't yet a high-level character. If, say, a level 2 mage with 300 hit points contracted a disease that sapped 250 hit points in the time it takes to say "Hakkar the Soulflayer sucks and ruins everything," that was devastating news for the poor noob. Worse, if they attempted to re-enter their body, respawn, and play again like a good WoW player, they encountered another nasty surprise: they were still infected. Yep, resurrection wasn't just for sentient, conscious beings anymore: Azeroth's malevolent viruses now refused to die with their hosts. So the level 2 mage would die, come back, and immediately die again, with the cycle repeating until the player rage-quit.
Within hours, Azeroth was all but a ghost world. Cities were littered with skeletons, anyone who tried to re-enter their body paid the price very quickly, and if the "bring out your dead" guy from Monty Python and the Holy Grail were around, he would've pulled in enough overtime to retire that week. It didn't help that, as Gamasutra pointed out, some high-level griefers summoned their inner Joker and became self-appointed agents of chaos. They would get infected, then purposely run around from town to town and infect everyone they could find, because ruining people's fun is the absolute height of hilarity.
Blizzard was flummoxed as to how to fix the issue. As developer John "No Relation To Johnny" Cash told PC Gamer, "Our choices were either to go through every pet in every server in every country in the entire world and check if it had corrupted blood and get rid of it, or get really hacky code in where every time you summoned a pet it would check and see if it had corrupted blood on it and get rid of it."
Finally, about a month later, Blizzard figured out how to solve the crisis, releasing a new patch that made it so Corrupted Blood could no longer be transferred to pets. Plus, it would now only affect those actively battling Hakkar. With that, the plague was over, and players were able to respawn and actually play the game once again. As far as all those bones go, who knows what happened to them?Maybe the village baker ground them up to make bread.
Interestingly, the Corrupted Blood plague might actually wind up helping humanity, instead of just aggravating a sizeable chunk of it for a month. As WHYY explains, professor Nina Fefferman of Rutgers University's Department of Ecology, Evolution, and Natural Resources began studying the digital epidemic in order to learn more about how people might react to a real-life plague.
After logging into World of Warcraft to witness the damage, she realized she too could be infected. "In all of the models that we built to predicted epidemics," she observed, "none of them included well-meaning people rushing towards the outbreak, and then having to get out, who were not themselves medically trained."
If such research means that more people will learn to stay away from plagues and other disaster areas unless they're properly trained to handle them, then World of Warcraft being virtually unplayable for a month would be completely worth it.