"This is a bone. Wow."
The Bone is one of the various pieces of equipment that the player can give to their Vulpin in Vulpin Adventure. The Bone is, as its name suggests, a long bone that resembles a femur of some description. It gives the Vulpin holding it a Stat boost of +5 attack.
The Bone is a rather uncommon drop from defeating one of the Flaming Fossils that live in the Desert Ruins. The rather strange thing about this is that there are no bones visible on the Fossil's body that resemble the Bone weapon.