Bat bones

Ew, it's a pile of bones.

Grand Exchange

Bone grinder

Robin

During Twilight of the Gods

Bring Pestle and mortar.

Source	Quantity	Chance per roll
Albino bat []	1	Always
Bat []	1	Always
Chaos Elemental (Members) []	5	1/12
Transmutation (Equilibrium League) [{'content': 'Requires appropriate material to transmute from.'}]	1–10	Special
Giant bat []	1	Always
Holy scarab scroll (Bone Conjure) []	1	1,578/33,611
Operating table (Senntisten Asylum) (3, Twilight of the Gods) [{'content': "Only if the player doesn't already obtained the item during Twilight of the Gods."}]	1	Always
Warped bat []	1	Always