A gas spore was a spherical floating creature. It had a central false eye and ten rhyzome growths on its top, which resembled a beholder's central eye and eyestalks. The difference could only be noticed as one approached the gas spore.
Being fungi, gas spores were non-intelligent creatures. Communities of gas spores existed peacefully in locations where food was sufficiently abundant. In the absence of food, gas spores hibernated and could remain in that state for centuries.
Gas spores that grew upon the corpses of dead beholders were known to carry the memories of their host. An infected humanoid could then access fragments of those memories.
Although harmless when feeding, the danger posed by a gas spore lay in its reproductive cycle. The creature deposited its spores into the body of a warm-blooded and sufficiently large creature (the size of a gnome or larger) by merely touching the creature. The infestation killed the host within a day if left unchecked, after which several tiny gas spores emerged from the corpse, reaching maturity within seven days. Mind flayers were usually ignored by gas spores.
A gas spore whose main body was hit by an attack immediately exploded, releasing poisonous gas and a large number of spores that reached a 20 feet (6.1 meters). Gas spores hit in the rhyzome growths did not explode.
Gas spores were thought to have first appeared as a consequence of parasitic fungi feeding off the corpses of dead beholders and becoming infected with aberrant magic; after a long period of adaptation, they acquired the ability to quickly sprout from any infected corpse.
The origin of gas spores was not unanimously agreed upon, however. Other sages maintained that gas spores had been purposefully created by beholder mages, while some believed that they had been created by mind flayers as a first line of defense, along with brown mold and shriekers. Others yet claimed that gas spores had been created by myconids with the purpose of serving as perimeter defenses for their colonies.
In the late 15th century DR, the deep gnome Xoblob, owner of the Old Xoblob Shop in the Dock Ward of Waterdeep, survived the detonation of a gas spore in the Underdark, which caused him to inherit a few beholder mannerisms and memories.
The poisonous spores released from a gas spore could be harvested and turned into a powder. A single dose of gas spore powder reached a price of 500 gp and could cause the same infestation in its victim.
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