18Dropped by
the bone is a ranged attack
Every connect lobs a bone that arcs and falls, and under the hood the game files it as a ranged projectile. Your ranged critical chance drives it and none of your melee buffs reach it, so flasks, a sharpening station and the magma stone all do nothing for that half of the weapon.
crowds multiply it
It throws one bone per enemy struck, not one per swing. Sweep through three skeletons and three bones go out. In a dungeon corridor that turns an ordinary broadsword into something that clears the room ahead of you, which is the whole reason to hang onto it past the point where the raw swing looks unimpressive.
getting one
Skeletons part with it rarely enough that nobody sets out to farm it. If one turns up on an early dungeon trip, use it until something clearly better replaces it.