The kerodroni (/ˈkɛrədroʊni/) is a long-bodied, black-handed stranger with a radio antenna emerging prominently from its mouth. The kerodroni carries its head in an upright posture, and stands with perfect balance, allowing its antenna to remain vertically aligned at all times. Its skin is smooth and soft to the touch, and emits a very slight electrical discharge. Its flesh is black, and its body cavity is filled with wires and cables that connect to the radio antenna's base. These wires have only minimal electric charge, and, like the appearance of the kerodroni's antenna, their arrangement varies between individuals. Only the kerodroni's skin and flesh are capable of regeneration, and only in the case of cuts less than a sixteenth of an inch in either width or depth, which take ten to fourteen days to close up.
The kerodroni appears on rooftops, balconies, awnings, and other lofty locations of at least nineteen feet in height (with a strong preference for significantly more elevated locations). When it first appears, it fades in from static and takes solid form over a period of time between 36 seconds and three hours long. This generation is accompanied by a crunching, fuzzy sound, which grows quiet as the kerodroni solidifies.
While the vast majority of kerodroni appear typical, 2% present with rusted, twisted, or broken antennae. These kerodroni typically exhibit erratic, violent behaviour, and tend to live drastically shortened lives.
The kerodroni's disposition is observant and precise. It spends most of its time perched motionless in high places, only occasionally flicking its tail back and forth. When it does move, it walks from place to place in direct paths, and does not wander. The kerodroni is adept at climbing, and its balance allows it to easily walk across any beam or cable strong enough to support its weight.
The kerodroni is a social stranger, and individuals of a similar appearance tend to form groups. Groups of kerodroni frequently rest together on the tops of buildings, where they twine their bodies together and point their antennae upwards to create tower-like formations1. When not at rest, individuals within a group groom each other by removing paper, string, and other debris from each other's antennae. Rarely, groups of kerodroni display some aggression towards individuals of a radically different appearance, and push them off of roofs or ledges, or grab and bend their antennae, but this cannot be thought of as a common occurrence, and lone individuals display no such xenophobia.
The kerodroni speaks only in numbers and phonetic alphabet words, which it broadcasts in radio waves2 across a wide range of frequencies, ensuring that its voice will be heard on any nearby radio. Half of all kerodroni speak in a masculine pitch, while the other half speak in a feminine pitch. The numbers and words that form its speech are spoken in regular intervals, and appear completely randomized, with no repeating patterns. The kerodroni's broadcasts are cumulative; radios around two kerodroni broadcast two overlapping voices, while larger numbers of kerodroni emit a cacophonous mess of audio.
The kerodroni displays a methodical intolerance of birds, and strangles, crushes, or otherwise mangles any birds it finds roosting. It is incredibly thorough in these acts, and in addition to mangling birds themselves, also pulls apart nests and destroys any eggs it finds inside. Despite these destructive actions, the kerodroni's demeanor remains detached, and most individuals kill birds with a quick, clinical precision. Rusted or damaged kerodroni, however, display overt ferocity, and even torture birds before killing them, sometimes going so far as to pluck out individual feathers, or break their wings and throw them off buildings.
In addition, large populations of kerodroni affect birds' behaviour in erratic ways. Some birds fly into windows or walls en masse, while others display extreme aggression towards one another. Still others eat and crush their own eggs, or refuse to roost at all, and instead fly in continuous circles before they drop to the ground from exhaustion. Over a long enough period of time, a kerodroni infestation can completely eliminate the presence of birds from an area within a city.
The kerodroni avoids contact with and retreats from sensitives, but, when cornered, stops moving, as though unsure of how to react. Physical interaction with sensitives is dangerous for the kerodroni, as any contact causes the cables inside its body to tighten and contract, forcing its body into a twisted, shriveled position. After twenty to thirty seconds of prolonged physical contact, even the kerodroni's antennae bends and crumples inward, as well.
Although this gradual pinching of form is not fatal in an of itself, the kerodroni is unable to recover from constriction, and while briefly touched individuals manage to survive (albeit with obvious deformities or hobbling motions), most spend the rest of their lives in a tightly coiled, shriveled position until dying of old age. Other kerodroni always strip the skin off of their damaged companions, but do not otherwise interact with them.
The kerodroni does not exhibit aging (beyond wear-and-tear) and instead dies suddenly, usually when at rest. Following death, its skin takes on a grey, ashy form, and crumbles apart to expose the kerodroni's antennae and wires. Other kerodroni that stumble across these corpses pull apart and scatter these wires, and plant the antennae firmly into the rooftop of the building on which the corpse rests.