The corderi (/kɔrˈderɪ/) is a dark brown stranger characterized by its hard, ribbed skin, as well as its indented eye markings and sharply curved claws. Its surface is plasticine and sounds hollow when tapped, with 0.07% of individuals producing a second tapping sound one to two seconds after being tapped or struck. The corderi's arms, legs, and tail tip lack this ribbing, and are covered, instead, with a soft, thin skin. Although the corderi's grey, slimy flesh radiates heat, the ribbed sections of its body act as insulation, and thus, only the corderi's arms, legs, and tail tip are warm to the touch. Its mouth contains small, evenly spaced teeth, and a short tongue which ranges in color from soft grey to a healthy pink, a hue shared by its gums. Its jaws tends to remain in a fixed, slightly open position, and its oral cavity does not connect to its grey tissue-filled internal cavity. The corderi has no particular odor on its own, but its flesh tends to absorb and take on the smells of its surroundings.
The corderi is a relatively vulnerable stranger. Although it does not respirate, it appears to require oxygen to survive, and drowns instantly when its mouth is submerged in water. Its body is also destroyed by fire, which causes its arms and legs to melt and its ribbing to grow brittle and crumble apart. It is similarly vulnerable to extreme heat and cold, and grows weak and dies in temperatures above 126°F or below -5°F. While its flesh is weak and possesses minimal regenerative ability (taking several months to heal from even small cuts, and with significant scarring afterward), its ribbed segments are difficult to pierce or bend, although numerous nicks and scratches do tend to accumulate over time due to natural wear and tear.
The corderi speaks in nonsensical human speech, albeit with a moderate-to-severe stammer depending on the individual. Its voice is always raspy and quiet, and is masculine 94% of the time, with the remaining 6% of individuals presenting with a more androgynous, child-like voice.
The corderi appears in tunnels, pipes, and other narrow passages. Sewage and drainage tunnels, abandoned underground railways and roadways, and the basements of sprawling, vacated buildings are common sites of a corderi infestation. It prefers narrow tunnels over wider ones, and never appears in areas which receive direct sunlight.
When it first appears, the corderi grows from a small, fetus-like form, which starts off smooth and pale in coloration, and grows larger and darker as it develops, with its characteristic ribbing appearing towards the end of its growth. Once development is complete, the corderi uncurls and stands up, grooming itself fastidiously to remove any dirt which may have accumulated on its skin during formation, before it scurries off into the shadows. Groups usually appear in small piles, which awaken in unison and scatter in separate directions.
Rarely, individuals appear inside small cavities beneath floors or inside walls, and die once they grow larger than the cavity's space allows. Any fully developed corderi always scratches at the wall or floor around a trapped individual in an attempt to free it, and stops only when the trapped corderi either dies, or is liberated from its confinement.
The corderi possesses a skittish and wary disposition. It moves in consistent, looping paths through its environment, avoiding all loud sounds, bright lights, and changes within this territory. It has the tendency to dig and tunnel, and is quite adept at hiding the entrances of these passageways from view. Although it does not swim, the corderi can navigate through small pipes and tunnels filled partially with water by laying on its back or side and pulling itself forward with its claws on the ceiling, keeping its mouth at least half-exposed to air. It often utilizes such half-submerged paths in order to conceal its territory. At shallow depths, the corderi's tunnels are twisting and chaotic, with maze-like junctions and dead ends. As it burrows deeper, however, these tunnels become straighter, with 90° turns and long corridors that correspond with latitudinal and longitudinal lines. Corderi infestations tends to be co-morbid with other subterranean strains.
The corderi displays some hoarding behaviours towards small, random objects, and carries them in its mouth as it travels along its path, eventually embedding them in the walls of its tunnels. Corderi tend to place objects in clusters, and in an area heavily infested with corderi, a single tunnel may contain hundreds of objects placed there by dozens of individuals, their arrangements forming intricate, mural-like designs.
Although the corderi is not violent towards others of their strain, it does display occasional coarseness towards nearby individuals. It is not uncommon for one corderi to roughly push or growl at another corderi, particularly in the case of unfamiliar individuals. The corderi at the receiving end of this aggression, however, does not tend to react to this incivility, and merely continues on, unperturbed. Otherwise, interactions between corderi tend to be brief, and consist of short "conversations" of tapping/stroking motions to the mouth and side of the face.
The corderi is capable of generating objects inside of its body, which appear to be duplicated from individual objects that occur in its surroundings. Most of the time, it duplicates simple, commonplace items such as spoons, nails, or pens, but more complex objects, such as phones or books, are not unheard of. These objects grow in a slow, organic matter. A pen, for example, starts off as a small plastic nib, and grows larger and more complex over time, as though it were a developing embryo, while a book blossoms outward from a clump of crumpled paper.
While these objects are compositionally identical to their man-made counterparts, they are immediately recognizable as fake. Bottles may possess half-inch-thick walls, for example, while cameras may display distorted, bulging sides. Complex mechanisms rarely work, and still other objects possess ridged, bumpy surfaces, duplication of features (such as jars with a lid on each end), or fusions of other features (such as un-openable magazines with spines on each edge). In addition, the corderi cannot duplicate man-made text with any degree of accuracy. Logos on the sides of duplicated soda cans, for example, appear as meaningless symbols, while books contain only crude lines or repeating sequences of lines or dots.
Rarely, a corderi will create a duplicate of another corderi's duplicated object, and any deformities in appearance continue to propagate and expand. As such, over a long enough timespan, objects within a population have the tendency to grow more and more meaningless and abstract, until the corderi generates curved, nondescript shapes, bulging plastic shells, and crumpled polygons which bear no resemblance to the original object.
This duplication appears both harmless and involuntary, and the corderi itself makes no indication that it is even aware of this process. Each corderi duplicates within its inner tissues between one and seven objects over the course of its life, and these objects do not distort its form or impede its life in any way.
The corderi is extremely wary towards sensitives, and watches them from a distance with nervous suspicion, running away once they get too close. The corderi will always choose flight over fight, and, when attacked, grows agitated and spasmic, rather than defensive and violent. It tends to abandon any territory into which a sensitive ventures.
The corderi sympathetically picks up nervous tics from the sensitives it encounters, even when these tics are not physically presented while in its vicinity. Proximity to a sensitive with a hand twitch, for example, will cause the corderi to pick up this trait in itself, while proximity to a sensitive with a stutter will cause the corderi's own speech to grow even more broken and stammering. These tics can even become injurious in the case of skin-picking or teeth grinding. In addition, strongly afflicted corderi seem capable of spreading these tics to others, and populations can quickly become overrun by these neurotic and often injurious actions.
At the end of its life, the corderi's nervous tics grow more pronounced, and its movements grow less and less co-ordinated, in turn. A dying corderi seeks out a quiet, secluded place, where it groans and wheezes, traces its fingers along the grooves between its ribbed stripes, tilts its head to place small pieces of garbage inside its indented eye markings, and taps its teeth one-by-one, as though counting them. Its companions give it a wide berth during its final days, and the corderi dies with a shuddering rattle, its eye markings losing their indentations to leave behind only a flat surface.
The corderi's flesh begins to rot and break apart within the next few days, while its ribbed sections separate and grow brittle. Other corderi hoard any objects left behind, but display no other interest in the corpse, which decomposes fully after several months.