The Bow of Bone is crafted from the bones of fallen undead. Its light construction allows it to fire faster than a normal bow and occasionally living foes felled by its arrows rise as undead themselves.
It is categorized as Forbidden Knowledge.
After 1 seconds of charging the bow begins firing arrows. It fires 2 arrows per second and has the same range of the Vanilla bow.
The arrows leave a trail of black smoke when shot, but this does not have any effect on the Aura or Taint in the chunk.
Sometimes after the enemy dies, a skeleton similar to the one raised by the Wand of Bone appears. The skeleton appears next to the place where the enemy died. Note that even though the bow description states that living enemies may spawn undead, anything killed by the bow, even animals and other skeletons, have a chance to spawn a friendly skeleton archer.
You can find the Bow of Bone in naturally spawned chests in Dungeons or MystCraft realms.