The cursed knife, as it has been called, is a most dangerous weapon. When used in battle, the wielder's mind is submerged by an overmastering will. Slowly, their hands turns, until the rusty blade is an inch from the neck, and then it seems to sing as it savegely slits one's own throat. Any adventurer with his customary elfin sword can easily spot any such cursed weapons by noticing the blade giving off a single pulse of blinding blue light as it is touched.

The cursed knife was last seen in 948 GUE, with the maze section of the First Level of the Dungeon of Zork.

SOURCE(S): Zork I, Dungeon