Araumycos Araumycos ( Dwarvish for “ Great Fungus ” ) was an enormous fungal growth that lived in the Upper Northdark and lay beneath the High Forest between the cities of Menzoberranzan and Ched Nasad . Description . Araumycos a huge life form , a single organism that covered almost all the parts of the Underdark beneath the High Forest , beginning at a depth of one mile ( 1 . 6 km . ) under the surface and ending at a depth of three miles ( 4 . 8 km . ) . It was believed to extend from the Shining Falls to the Lost Peaks and from Tall Trees to the Hall of Four Ghosts , wholly occupying the labyrinth of tunnels and caverns that existed beneath the High Forest . But it seemed that it had reached its peak of volume since it no longer grew through other territories . History . Centuries ago the area where Araumycos was located was mined and occupied by the dwarves of Ammarindar during the time of the elven realm Eaerlann . The dwarves of ancient Ammarindar spoke of their mines located in the region beneath the elven realm of Eaerlann that were abandoned to the slow , inexorable growth of Araumycos . The elves have legends that date back farther still , linking the birth of Araumycos to the fell sorceries of the Vyshaantar Empire , but so little was known of that era , even among the long memories of the elves , that no origin could be conclusively determined . Araumycos was thought by some to be the oldest living creature on Toril ; even the gods did not speak of it , and divine divination s regarding the titanic fungus always failed . Some believed that the creature was an avatar of Psilofyr , the lord of the Myconids , but this was only a theory . Since the Spellplague , the rumored awareness of Araumycos was proven . Referring to itself as “ King Araumycos , ” it brought millions of myconid s under its domination , and tried to do the same with any sentient creature within hundreds of miles through strange nightmare - dreams ( which the drow called " golhyrrl ' fhaazht " or “ the Dream Trap ” ) that spoke of the comfort of the mass and the hopeless chaos of individuality . Abilities . Araumycos was immune to magic and greatly resistant to psionic energy . Some areas of Araumycos could be attacked with normal weapons or were vulnerable to fire , acid , and other means , but destroyed parts grew back within a short time . Prior to the Spellplague it seemed that the fungus was unaware of intruders and their destructive ways , but there were rumors telling otherwise . Araumycos had terrible defenses such as poisonous gas , enormous psionic power , and it could manifest slimy creatures similar to ooze s . Araumycos could also use spores to dominate the will of victims and emit substances which could animate skeletal remains upon which they cling . From time to time , without explanation , large sections of Araumycos withered and decayed , revealing ancient , undisturbed caverns . These caverns sometimes contained ancient ruins and were greatly sought after ( especially by Shade Enclave ) . They were eventually reclaimed , either in hours or centuries . Locations . Although Araumycos for the most part completely filled the tunnels it inhabited , a few area were not entirely covered . Blacktooth Rock was an intersection of tunnels in ruined Ammarindar named for a large black stalactite that looked like a fang biting into fungus . The intersection was a layered chamber carved by the dwarves . It was passable but full of Araumycos .