"This is an ancient artifact made of an unknown material. It is rectangular in shape, very thin, and inscribed with unreadable ancient runes. When carried, it grants the one who carries it ESP, and reduces all physical damage done to the carrier by half. It also protects from magic missile attacks. Finally, its power is such that when invoked, it can charge other objects."
It is the object of the Tourist's quest and, for many Hackers, the biggest reason to consider wishing for an artifact. You can even pick locks with it, if that's worth anything to you.