A mass slaughter of World of Warcraft players has devastated the popular online roleplaying game.
Hackers were somehow able to gain control of the game and kill characters at will.
Normally players of WoW are unable to kill each other unless they each agree to a duel, but the hackers worked out how to override those protections.
The slaughter saw entire cities wiped out across Azeroth - the world of, well, Warcraft. The populations of Stormwind, Orgrimmar, Tarren Mill, Ragnaros, Draenor and Twisting Nether were put to the hackers' sword.
In an echo of the South Park episode 'Make Love, Not Warcraft', it appears as though the hackers were able to rampage unhindered for hours.
But the details of the hack are still unclear.
"We don't know exactly what they did, but somehow they were able to kill every single player's character in that city and every single computer controlled character - and they were doing this repeatedly," said Olivia Grace, of Joystiq and WoW Insider, to the BBC.
The game's makers Blizzard Activision said that the hack had been fixed - and they were leading a "thorough investigation":
Earlier today, certain realms were affected by an in-game exploit, resulting in the deaths of player characters and non-player characters in some of the major cities. This exploit has already been hotfixed, so it should not be repeatable. It's safe to continue playing and adventuring in major cities and elsewhere in Azeroth.
As with any exploit, we are taking this disruptive action very seriously and conducting a thorough investigation. If you have information relating to this incident, please email email@example.com. We apologize for the inconvenience some of you experienced as a result of this and appreciate your understanding.
One hacker - named Jadd - has already claimed responsibility.
Writing on the Ownedcore Forums, he said that he thought it was "funny".
"We didn't do any permanent damage. Some people liked it for a new topic of conversation and a funny stream to watch (sodapoppin), and some people didn't. The people who didn't should be blaming Blizzard for not fixing it faster (4 hours of obvious use is sad).
It's not like I added 20000000 gold to everyone's inventory, and broke the economy; but look at the big Chinese gold seller companies, who are doing this every day. Now ask yourself who is really ruining the game. It's not us.
That's my justification."