Players in the “World of Warcraft” online game have suffered a demonstration of the dangers of self-replicating code. The designers of the game added a monster that could inflict a self-propagating disease on player characters, but did not limit the ability of the disease to spread. Consequently, the disease spread out of control, making the whole game almost unplayable, and spoiling the fun of many players.
The game's developer, Blizzard Entertainment, modified the disease so that spread was limited to certain game areas, thus stopping the epidemic.
This incident takes place in a game and stretches the limits of the definition of a computer virus, but it is a reminder of the dangers of any self-replicating code.