This is a warning that has been running around the internet today. If you play Borderlands 2 with random folks, you are increasing the risk of an infection of your Borderlands 2 save file. This save file denies respawning of characters and cannot be remedied currently. As of right now, the only folks that seem to be infected are Xbox 360 and PC players.
So, if you see that your savefile for Borderlands 2 is called, "Graveyard.sav," your only option is either delete the file and start the game over or send your save file off to a member of the modding communities.
It is unknown if this is a malicious attack or simply a glitch. Gearbox has not rleased any statements on this problem yet.
Here is a post from GameFAQs (which is currently down) that the Better Gaming Bureau pulled:
What is graveyard.sav? What does this have to do with me?
When you get hit by the glitch that turns your save into graveyard.sav, upon entering FFYL and then subsequently dying for whatever reason, you will never respawn. You die and go into a free roam camera. If you try to load another character, dashboard, restart your xbox, etc, your save data is completely gone and there is no hope of recovering it at that point, as it is renamed graveyard.sav and is missing the majority of the data it once had.
What?! How did I get this?
The glitch originated with the modding community and may or may not have been accidental. It spread from there, and it passes from the infected player to all other players in the game with said infected player. At this point, it’s a terrible chain, and chances are it passed to you through some randoms.
Good luck!