The isodromi (/ˈaɪsəʊdroʊmi/) is a long-legged, looming stranger. Its surface is a pale, blueish color, and its translucent frame glows in the dark with the luminosity of a flickering television screen. Like the eodromi, it possesses a ghostly, ethereal nature, and cannot be moved or physically interacted with. The isodromi passes through walls, fences, and other solid planes with no distortion or destruction of either the object or itself, but respects the fidelity of any surface on which it stands. When touched, it creates the sensation of searing heat, but causes no burning of the flesh.
A small blue flame hovers above the isodromi's head and accompanies it at all times, quivering as would the flame of a candle. Like the isodromi itself, this flame gives the sensation of extreme heat when touched, but radiates no actual warmth.
The isodromi grows distorted or invisible when exposed to fire or water, or when an object passes through it, but it does not display any permanent ill effects, and flickers back to normal once contact ceases.
Its voice is throaty and echoing, and it speaks at an all but inaudible volume heard only on the edges of the isodromi's longest breaths. It never speaks in words, but rather, sounds like a crowd of people crying out in terror.
The isodromi's generation is not specific to any environment, and instead seems to be a by-product of large scale but unseen shifts within a population. Upon its generation, the isodromi appears as a small, rounded, legless form, which grows in size in a rapid burst accompanied by a searing flash of light. It tends to occur in tandem with others of its strain, with four to eight isodromi generating in even distribution within a city.
The isodromi's disposition is foreboding and transient. It wanders with slow, ambling steps as it makes its way through empty city streets, shopping centers, and parking lots. It reacts to nothing, and does not engage the world in any way.
The isodromi is also one of the few strangers capable of wandering outside of cities, a behaviour which occurs only near undeveloped stretches of desert. The isodromi never wanders more than several miles away from population clusters, however, and flickers out of sight once it roams too far, its death unseen but presumed. In addition, while outside of the city, is appears vulnerable to weather, as well, and its body scattered by heavy dust storms. Occasional grouping behaviour is observed only in this context, with small clusters of isodromi circling the wastelands around large desert metropolises, vanishing once people walk too close.
The isodromi's presence induces symptoms akin to radiation poisoning, and thus, causes great harm to all sensitives who encounter it. Headaches, fever, and nausea occur within ten to twenty minutes, with severe exhaustion setting in shortly afterwards, followed by shocks and seizures. While not all encounters with the isodromi prove fatal, even one hour of exposure is enough time to cause lethal effects. Following an encounter of this length, even if medical attention is sought out, death occurs within two to seven days. In addition to this, hair loss, teeth loosening, and skin discoloration occur in all corpses in the isodromi's presence.
The isodromi does display some attraction to sensitives, but cannot be said to seek them out, as any attraction represents only a slight deviation from its random wander. Nonetheless, because it is able to move through solid objects, there is a non-zero chance of an isodromi encounter regardless of location.
Although the isodromi is non-violent, due to its effects and indestructibility, the only guaranteed way to survive an isodromi encounter is to avoid it altogether.
"It's a sweltering summer day, and the windows are all open, so along with the smell of hot chilaquiles, so too waft out the sounds of arguments from some homes, laughter from others. I watch from the rooftop as the creature grows closer, wanders down the street, intersects with a newspaper stand and then, begins to pass through the building. This one's a big one, three stories tall, and I can see its head now in one woman's kitchen. She walks to the oven and her foot goes right through the side of its snout, and I want to shout out, to say something, I'm terrified for her, but then she steps away, and it doesn't seem to have done a thing.
I watch it for a while now and in my hunger run my tongue over my gums and teeth. One of my molars feels so much looser than the rest. My little brother's on the back ledge and he looks up, and calls "¡hermana!" to me, and I smile back, just as the thing moves through him, and for just a second, his smile fades, and I lean down, wiggle my tongue, and that tooth falls to the ground below, a penny down a well." Piñero, Evalisse. Immigration Journals, 55
The isodromi has only a minimal effect on non-sensitives, however, and average-sized infestations are responsible for only a 0.4-3% rise in cancer rates within an affected city.
ISOSOVINDRI ISODROMI: certain individuals, known as isosovindri isodromi, have much stronger effects than average, causing death within minutes as skin sloughs off, muscles soften and detach, and blood becomes corrupted. An isosovindri isodromi is identified by the strong breeze that circles it, as well as the halo of incidental objects such as newspaper pages, plastic bags, and small pieces of trash that billow around it in swirling formations.
Throughout the course of the isodromi's life, it displays an exponential decrease in luminosity and opacity as its particles decay. As this occurs, its effects on sensitives decreases, until it causes only slight exhaustion and rash, its weakened body nearly invisible from most angles. At the end of its lifespan, the final vestige of its form blows away like smoke in the wind, leaving behind a brief, swirling breeze.