Bonemaw (click for map image) is a parasite in the Anetarx Magicae Santucary, the large area extending out of the western part of second floor: PH "a fearful scavenger magicae".
Map points for "arxmentis.txt" map files (for all Arx Mentis named map points, see this quest entry):
Bonemaw is heavy on DOT effects: It casts two random single-target spells: "Bonemaw Rot" (46,000 dmg/tick for 3 ticks; 50 corruption counters) and "Withering Limbs" (26,000 dmg/tick for 3 ticks + reverse 3,000-point damage shield; 65 curse counters).