Araumycos

Araumycos (Dwarvish for “Great Fungus”) is an enormous fungal growth that lives in the Upper Northdark and lies beneath the High Forest. Centuries ago this area was mined and occupied by the dwarves of Ammarindar during the time of the elven realm Eaerlann. , Today these caves and mines are inhabited by a huge life form called Araumycos. It is a single organism which covers almost all the parts of the Underdark beneath the High Forest, beginning at a depth of one mile under the surface and ending at a depth of three miles. It is 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 exist beneath the High Forest. But it seems that it has reached its peak open volume since it grows no longer through other territories.

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 is known of that era, even among the long memories of the elves, that no origin can be conclusively determined. Araumycos is thought by some to be the oldest living creature on Toril; even the gods do not speak of it, and divine divinations regarding the titanic fungus always fail. Some believe that the creature is an avatar of Psilofyr, the lord of the Myconids, but this is only a theory.

Abilities
Araumycos is immune to magic and greatly resistant to psionic energy. Some areas of Araumycos can be attacked with normal weapons or are vulnerable to fire, acid, and other means, but destroyed parts will grow back within a short time. It seems that the fungus is unaware of intruders and their destructive ways, but there are rumors telling otherwise. Araumycos has terrible defenses like poisonous gas, enormous psionic power, and it can manifest slimy creatures similar to oozes. Araumycos can also use spores to dominate the will of victims and emit substances which can animate skeletal remains upon which they cling.

From time to time, without explanation, large sections of Araumycos wither and decay, revealing ancient, undisturbed caverns. These caverns sometimes contain ancient ruins and are greatly sought after (especially by Shade Enclave). They are eventually reclaimed, either in hours or centuries. ,

History
Since the Spellplague, the rumored awareness of Araumycos has been proven. Referring to itself as “King Araumycos,” it has brought millions of myconids under its domination, and tries to do the same with any sentient creature within hundreds of miles through strange nightmare-dreams (which the drow call golhyrrl' fhaazht or “the Dream Trap”) that speak of the comfort of the mass and the hopeless chaos of individuality.