From Kotaku:

“A World of Warcraft subscriber has accidentally been given a powerful in-game item normally reserved for internal testing. And what’d he do with it? Why, he used it.

Yes, instead of doing the right thing and returning the item (”Martin Fury”, an in-game shirt), he kept it and went out on a bit of a killing spree. Because the shirt allowed the wearer to destroy everything within a 30-foot radius instantly, the user – Karatechop – managed to rack up an impossibly impressive set of achievements in the game, including the destruction of the normally-difficult character “Flame Leviathan” in a single blow.

While his account has since been banned, with Blizzard accusing him of cheating to obtain the item, Karatechop maintains that the item was accidentally presented to a guild mate of his by Blizzard, in an official Blizzard email, as part of the restoration process for a hacked character.

Who to believe, who to believe?”

I would’ve done the same thing. =)