Hit Dice:3 to 6+2
Armor Class: 3 
Attacks: Bite (1d6+2)
Saving Throw: 11
Special: Piercing weapons due half damage, 25% magic Resistance, Regenerate, Surprise, Undead, Web
Challenge Level/XP: 4 - 6/120 - 400
Bone Spiders are malign spirits who form their bodies from the bones of the dead and who haunt the ancient barrows, tombs, bone pits and crypts of the world growing and gaining power as they add more bones (fresh and ancient) to their form. Bone Spiders are always hungry, are always thirsty and will devour all living things they encounter in the places they call home and slightly beyond. A Bone Spider cannot be truly destroyed as it is a spirit inhabiting a manifested form. If a Bone Spider is defeated it will manifest in a new lesser form (3HD) in 1d6 days after its defeat and return to the work of devouring and growing.