The disease originated from Hakkar the Soulflayer -- the boss of this very initial 20-player raid Blizzard released. Hakkar would toss Corrupted Blood on gamers and it would damage them for wow classic gold about 10 minutes. Players would spread the impact to others if they got too near those infected. After the 10 seconds were completed, or players finished the boss battle, the damaging effect was supposed to end. Only it did not.

A programming supervision allowed the debuff to disperse beyond the website of this Hakkar boss struggle and to the world at large. Hunter characters may summon and dismiss pets to fight at their side at will. Once dismissed, all of the effects on the pets are paused until it's known as back out again. In consequence, the pets could contract Corrupted Blood during the boss fight, vanish then display the symptoms again elsewhere in the world map when they were summoned. There it would spread to other pets and players that came in contact with them.

Cities such as the dwarven city Ironforge and orc city Orgrimmar were overrun within hours. Non-playable personalities, who couldn't die due to special coding, would also catch the effect, meaning any participant who passed them could receive Corrupted Blood.

Once word got out, players hunted frantically for news about what was going on.

"The entire world chat would burst any time a city fell," says Nadia Heller, an ex-World of Warcraft player whose character lived through the episode. "We kept a close attention not only on our guild chat but on world chat as well to see where not to go. We did not want to best place to buy wow classic gold grab it."