A virus most often associated with jailbrokeniPhones and iPods (very very rarely happens at all). Mainly because jailbreaking leaves them wide open. The Passcode of Death takes your original 4 digit passcode and creates a random 10,000 digit passcode. Thus making it un-unlockable. Then making you force to restore it. Bad news if it is jailbroken because none of that stuff can be backed up.
After I got my new Cydia theme my iPhone got the Passcode of Death!!Now I have to get I all over again. :(