The nerodroni (/ˈnɪərəʊdroʊni/) is a serpentine stranger with dark grey and black stripes, black eyes, and chalk-colored lips and eye-rims. Its nails are dark and curved, while its teeth, gums, and tongue are white and glistening. The nerodroni's skin is smooth and slick, but not wet, and leaves a slight pigment behind on the hands when rubbed vigorously, although the nerodroni does not tend to stain its environment. Its flesh is black and oily, and its body is filled with nondescript organs which float in an inky, viscous fluid.
The nerodroni is characterized by the strong light that it emits from a small rectangular plane that floats inside its mouth, which it holds open at a constant 14° angle. The light emitted by the nerodroni behaves similar to the beam of light from a film projector, and displays a flat white rectangle when it lands on any flat surface.
The nerodroni exudes a harsh, toluene-like smell, its odor strong enough to cause light-headedness when inhaled at close range. Its regenerative ability is somewhat below-average, taking several weeks to heal from even minor cuts, and it tends to bleed out when deeply lacerated.
The nerodroni does not speak, and emits no sound save for a series of rhythmic and nearly inaudible whirring clicks.
The nerodroni generates in pipes and hollows 35-76 feet below human constructions. It never appears beneath clean or well-maintained areas, and instead generates below decrepit, trash-filled corners and dim, dreary spaces. The nerodroni displays a strong predisposition towards commercial districts, with only occasional generation in factories or other industrial spaces. No nerodroni has been observed beneath strictly residential areas.
It flickers into view with a dim but sudden glow of light, its body already matured. A small minority (0.28%) of nerodroni do not survive this initial manifestation process, and instead, flash into being as twisted, shriveled husks, their bodies breaking apart into glowing cinders that fade to black and then dissolve within three minutes.
The nerodroni's demeanor is calculating and surreptitious. It is a highly social stranger, with a tendency to form groups consisting of 4-18 individuals. Although the nerodroni generates only by itself or in pairs, individuals move towards others within the strain and congregate in underground chambers, which they expand in a meticulous manner, compacting dirt with their hands and utilizing pre-existing pipes and hollow passageways to allow many entrances and exits from these lairs. Once within a lair, entrances are sealed up tightly, and re-opened only in the case of new additions to the group.
Within these nests, nerodroni cling to the walls and ceiling and look downward, their glowing projections pointed at a single point in the center of the chamber's floor. Nerodroni display a marked order to their social interactions — they arrange themselves roughly by size, with the largest individuals positioning themselves in the upper regions of the chambers. These larger, more dominant nerodroni claw with derision at any smaller individuals who attempt to crawl too high, although actual fights are unobserved.
Because the nerodroni lives in isolated and often completely inaccessible areas, interactions with sensitives are few. When sensitives do enter their lairs, the enclosed clusters of nerodroni react with a hissing and writhing, their teeth glinting and their claws tapping against the ground. These groups continue to coil and re-arrange themselves as the sensitive stands in their presence, although this behaviour ceases after several minutes of inactivity on the part of the sensitive.
When provoked, the nerodroni attacks with its claws (possessing no ability to move its jaws) or by constricting around the sensitive, but generally ceases these attacks as soon as the sensitive is subdued, and does not go out of its way to murder sensitives.
When a memory is forgotten by a person nearby, whether through transience, brain damage, or death, the visual images embedded in this memory are projected by the nerodroni. These crude images resemble jerky and low-resolution home movies, with distortions influenced by the images' origin as neural signals, with some sections appearing wholly abstract (typically seeming "scratched over" or fully white or black). Although each individual nerodroni projects only vague segments of a larger whole, the combination of the overlapping projections creates full, if still blurry, images1.
Groups of nerodroni observe these images over and over, while displaying no particular reaction aside from an occasional flicking of the fingertips or slight wavering of the head in the case of extremely violent images. Each loop of the memories appears to degrade the image's fidelity, with some memories degrading faster than others; some memories are looped thousands of times before the image becomes too faded to discern, whereas other memories are able to be looped only a handful of times. Certain, rare memories are interrupted before their end, burning up like a stopped reel of film.
At the end of the nerodroni's life, its light grows dimmer in conjunction with the quieting of its whirs. Once its sound stops completely, its light flickers out, and it collapses to the ground, its body shriveling up and turning completely black. This ribbon-like corpse remains for only several seconds, before it burns apart, alighting nothing around it but leaving behind no ash. Other nerodroni react only insofar as to close up the gap left in the arrangement.