An unintentional bug has caused the spread of an incurable plague through the Borderlands 2 universe, leading to the permanent death and deletion of all characters that get infected.
One feature that was removed from Borderlands 2 before release is “badass” mode. In badass mode, players receive more powerful weapons and artifacts than in normal mode, but their characters get deleted permanently instead of respawning when they die.
This badass mode was disabled before the game was released, but it wasn’t removed entirely. As a result, players with modded Xbox 360 consoles were able to flip a flag and enable it again.
Problem is, players who participate in multiplayer games where one of the players is in badass mode get pulled into that mode themselves. There is no way to know in advance if a badass is among the players of a specific multiplayer game, thus it is impossible to avoid being infected. There is also no cure yet.
If you are a Borderlands 2 Xbox 360 player, the only precaution you can take until a patch is released is to avoid playing with strangers.
Gearbox acknowledged the problem, explaining that it has already prepared a fix but it will take some time to pass through Microsoft’s patch certification process.