As World of Warcraft turns 20 years old, we've been looking back at how the influential MMO changed the DNA of videogames as a whole, as well as remembering specific moments like the time adding playable dragonfolk brought a decade-old loot system to its knees. One incident stands out in terms of reaching beyond the world of videogames though, and that's the Corrupted Blood plague.
In 2005, a bug allowed a damage-over-time effect from a raid event to spread outside the confines of the boss fight it was designed for. The Corrupted Blood debuff was created to affect players as they fought Hakkar the Blood God, lowering their health and splashing from player to player if they stood too close. When it first escaped containment, nobody knew where it came from—they just logged on to find streets full of skeletons in the cities of Azeroth.
