The thin, frayed string of this bow appears unusable, but when it is drawn a solid but invisible arrow becomes tangible. The lich Tansheron gave this bow to his Watcher, the guardian of his keep who stood atop a tower with neither entrance nor exit. When anyone approached, down would fall a never-ending rain of phantom arrows until they were dead or fled. How this bow was wrested from the Watcher's hand is not known, but would probably make a great tavern story.
Note: avoid equipping normal arrows on your character, else the bow will fire these instead of the phantom arrows.
Tansheron's Bow, also known as Tansheron's Shortbow, is an enchanted weapon +3. Unlike normal ranged weapons, this bow creates its own arrows which deal 1d6 points of damage and are also +3 enchanted. The bow can create unlimited arrows and use physical arrows from the ammunition slots as well. It's not recommended to fire non-enchanted arrows from this bow, because the bow's arrows deal the same amount of damage and you could waste ammunition slots which could be used to store other ammunition. The bow has a range of 75 feet, which is standard for shortbows.
This item is sold exclusively by an unnamed merchant in Trademeet, after solving the genie problems.
Another is in the possession of Cattie Brie, one of the companions of Drizzt Do'Urden when encountered after leaving the Underdark. She will drop the bow upon death, but to accomplish this either requires recruiting Drizzt to aid in the siege of the tombs under the Graveyard District and somehow having her die to the vampires, or openly choosing hostile dialogue against Drizzt when encountered and having to fight his party. This particular version is identical mechanically, but strangely it uses the inventory icon and item description artwork of the Shortbow +1. However, this distinction exists for the player's benefit: if in the possession of this other version after finishing the business in the Graveyard District in Chapter 6 a character named Malchor Harpell will teleport in and attempt to take any and all of the equipment owned by Drizzt's party. If dropped and picked up he still appears, and on a third appearance he will cast a unique Mass Imprisonment on the party. Even if the party is protected via various immunities such as Berserker's Enrage or Spell Turning, he will appear once on every map henceforth and will attempt to initiate dialogue with the player infinitely, which breaks a lot of game scripts and also prevents the player from saving without going into a different building. The only way to use this bow, or any of Drizzt's party's gear, is to stash them in a container in Watcher's Keep until the player proceeds to Throne of Bhaal where his script no longer runs.