This is an older story, back from when I used to play Warcraft. I remember this incident and going through the major alliance city, Ironforge afterwards. I was wading knee deep through corpses.
The Corrupted Blood incident was a virtual pandemic in the MMORPG World of Warcraft, which began on September 13, 2005, and lasted for one week. The epidemic began with the introduction of the new raid Zul'Gurub and its end boss Hakkar the Soulflayer. When confronted and attacked, Hakkar would cast a hit point-draining and highly contagious debuff spell called "Corrupted Blood" on players.
The spell, intended to last only seconds and function only within the new area of Zul'Gurub, soon spread across the virtual world by way of an oversight that allowed pets and minions to take the affliction out of its intended confines. By both accidental and purposeful intent, a pandemic ensued that quickly killed lower-level characters and drastically changed normal gameplay, as players did what they could do to avoid infection. Despite measures such as programmer-imposed quarantines, and the players' abandoning of densely populated cities (or even just not playing the game), it lasted until a combination of patches and resets of the virtual world finally controlled the spread.
The conditions and reactions of the event attracted the attention of epidemiologists for its implications of how human populations could react to a real-world epidemic.
History
The epidemic began on September 13, 2005, when Blizzard introduced a new raid called Zul'Gurub into the game as part of a new update. Its end boss, Hakkar the Soulflayer, could affect players by draining their blood and using it to heal himself. By intentionally poisoning one's own blood using a debuff called Corrupted Blood, which did a significant amount of damage to the player over time, Hakkar would drain blood and apply the disease to himself, allowing him to be killed. However, Corrupted Blood could be passed on between any nearby characters, and would kill characters of lower levels in a few seconds, while higher level characters could keep themselves alive. It would disappear as time passed or when the character died.
Due to a programming oversight, when hunters or warlocks dismissed their pets, those pets would keep any active debuffs when summoned again. Non-player characters could contract the debuff, and could not be killed by it but could still spread it to players; in effect, this turned them into asymptomatic disease carriers and a form of vector for the debuff.[1] At least three of the game's servers were affected. The difficulty in killing Hakkar may have limited the spread of the disease. Discussion forum posters described seeing hundreds of bodies lying in the streets of the towns and cities. Deaths in World of Warcraft are not permanent, as characters are resurrected shortly afterward.[2] However, dying in such a way is disadvantageous to the player's character and incurs inconvenience.[3]
During the epidemic, normal gameplay was disrupted. The major towns and cities were abandoned by the population as panic set in and players rushed to evacuate to the relative safety of the countryside, leaving urban areas filled with dead player characters.[4]
Player responses varied but resembled real-world behaviors. Some characters with healing abilities volunteered their services, some lower-level characters who could not help would direct people away from infected areas, some characters would flee to uninfected areas, and some characters attempted to spread the disease to others.[1] Players in the game reacted to the disease as if there were real risk to their well-being.[5] Blizzard Entertainment attempted to institute a voluntary quarantine to stem the disease, but it failed, as some players didn't take it seriously, while others took advantage of the pandemonium.[1] Despite certain security measures, players overcame them by giving the disease to summonable pets.[6]
Blizzard was forced to fix the problem by instituting hard resets of the servers and applying quick fixes.[2] The plague ended on October 8, 2005, when Blizzard made pets unable to be affected by Corrupted Blood, thereby rendering it unable to exist outside of Zul'Gurub.
Reaction
At the time, World of Warcraft had more than two million players all over the world. Before Blizzard Entertainment commented on the outbreak, there was debate whether it was intentional or a glitch. On Blizzard's forums, posters were commenting about how it was a fantastic world event, and calling it "the day the plague wiped out Ironforge." An editor of a World of Warcraft fan site described it as the first proper world event. After the incident began, Blizzard received calls from angry customers complaining about how they just died. Some players abandoned the game altogether until the problem was fixed. The hard resets were described as a "blunt ending" by Gamasutra.
The people who spread the disease out of malice were described by Security Focus editor Robert Lemos as terrorists of World of Warcraft. He commented that this might be the first time a disease passed from player to player in a game.
Jeffrey Kaplan—a game designer for World of Warcraft—stated that it gave them ideas for possible real events in the future. Brian Martin—independent security consultant for World of Warcraft—commented that it presented an in-game dynamic that was not expected by players or Blizzard developers and that it reminds people that even in controlled online atmospheres, unexpected consequences can occur. He also compared it to a computer virus, stating that while it is not as serious, it also reminds people of the impact computer code can have on them, and they're not always safe, regardless of the precautions they take.
That particular raid, Zul'Gurub kicked ass btw. I loved doing that back in vanila warcraft.
