This is a weapon used by a barbaric race of unkempt half-giants living in and near mountains. It was hard to get informations about this weapon, as they speak a language nobody can understand, even magic means of communication failed. So all our results are due to testing while we made the barbarians drunk. They look rather ridiculous in their short trousers made oh leather and their hat with a brush attched to it, but that´s not important for the use of the weapon.
It is a long and hollowd out stick, way to large to carry it comfortably and impossible to swing or use to stab. So we can only guess that the barvarians (they call themselves "Barvarians", they can´t even pronounce Barbarian correctly) breathe into one end and due to their foul breath kill everybody on the other end. Or they use them to cause vibrations in the rocks (an instrument of this size might produce a sound so low that rocks start to vibrate). In the resulting landslides any attacking army would be destroyed...

But as I already said, this is just speculation.