When fighting the Skeletal horror, it will drop the Arm and lower its combat level from 130 to 124. The player must pick up and bury the Arm or it will return to the Skeletal horror and regenerate its life points and return it to its previous combat level. Burying it will make the Skeletal horror stay at its current combat level of 124.
It is not possible to say this item's name in quick chat, since it will say "Too many results. Please refine your search."