From D&D Wiki
Lacuna, the void, has earned its hallowing name. It's origins frame the story of this dark weapon. In the lands of the dwarves, a great black dragon continually attacked and destroyed many settlements and convoys. The dwarves fought back with all they had but could not bring down the great beast. As it happens, an oppurtunistic raptoran had been watching the attacks with great interest. Using his vast arcane powers, he controlled the wind to force the dragon low to the ground where the dwarves could slay him. The dragon was mortally wounded and flew till it fell from the sky. The raptoran followed the wyrm and cut out its heart as it still beat. He placed the heart into a cold iron morningstar with a black lorken handle. The raptoran of ages past has since been lost to tume, but his cruel side arm remains, passed down to those who revel in its abyssal powers. It has slain many from dark elves to fire giants, and hell hounds to liches.
Lacuna is a +2 cold iron acidic burst morning star. Once per week it can cast a line of acid equivalent to a mature black dragon. 3 times /day the weilder may cast globe of darkness as a 10th level caster. Once per day the weapon can expell an acid fog which fills a space 30'x30' and 10' high. It lasts 4 rounds or untill dissapated by a strong wind. The cloud grants total concealment to those looking in, and partial concealment to others inside the cloud 10' away or less. The cloud deals 2d4 acid damage on contact and deals 1d6 initial constitution damage and 1d6 secondary constitution damage upon inhaling as a poison. When danger is nearby the heart begins to beat warning the weilder.