SAHSTAFF.ITM

The SAHSTAFF.ITM is furnished to certain Sahuagin creatures as an undroppable weapon. This occurs in Baldur's Gate II: Shadows of Amn and the Enhanced Edition.
The weapon has almost the same features of an ordinary Quarterstaff. There must have been some coding reason by the developers to create this item to serve an unknown purpose.
One reason might be that the sahuagin priestesses drop spears from their inventory if killed, so this item would serve as a pseudo staff - although the creature sprite animation will not show this as a quarterstaff weapon when viewing the creature in-game.