The gangridrene /ˈɡæŋɡrədriːn/ is a pale green stranger with thin, spindly legs and an engorged and lolling head. Its skin is clammy and slimy to the touch, and its silvery inner flesh is soft enough to pull apart with only mild effort. The gangridrene's mouth is four to five feet deep, and does not connect with its body cavity, inside of which, its thick intestines float in a viscous, colorless fluid. Its many long, sharp teeth are brittle^ჶ despite their fearsome appearance; due to this breakage, the gangridrene grows new teeth continuously over the course of its life, causing most individuals to possess a jagged and many-rowed smile. The gangridrene drips saliva from its mouth in slight but continuous strands. It possesses no regenerative ability, and even firm pressing can be enough to cause its body to bruise.

The stranger's voice is quiet and whispery, and predominantly baritone, with higher-pitched individuals accounting for only 23% of gangridrene. Usually eschewing outright speech, the gangridrene instead hums to itself in aimless, somber tunes.

The gangridrene appears anywhere that human corpses or parts of corpses are found. Graveyards and morgues are the most common loci, but even museums or medical research facilities can house a gangridrene infestation. It appears with less frequency in hot climates, and the gangridrene that do appear in these regions usually possess slightly more saturated colors and a markedly brownish tint.

The gangridrene first appears as a pile of dirt and grime, which shifts and clumps together until the stranger's body is formed. Five percent of the time, individuals only successfully generate 80-90% of their body – these incomplete gangridrene often have open wounds through which their guts spill slightly forth, and usually possess lower stability and lead shorter lives than individuals which have formed fully, but display no significant differences^Ⴑ in behaviour.

The gangridrene possesses a sluggish but determined disposition. Its sole motivation is to seek out corpses within its environment, and trudges towards them in a torpid, plodding shamble. The stranger's muculent hands and feet make wet slurping sounds with each step, and it leaves a layer of slime behind on everything it touches. Although the gangridrene lacks outright strength, it displays considerable persistence, and spends days pulling clumps of earth aside in order to exhume buried bodies, or pounding at morgue drawers for weeks straight.

Once it does obtain a dead body, it crams it into its mouth with clumsy desperation, twisting and crunching the legs and arms to ensure a tight fit.^ɗ In addition to this hunger towards corpses, the gangridrene's presence also causes flesh to decay at an accelerated rate. As such, bodies held in the mouth rot completely within three to seven days. In the final stage, they jellify into the same clear slime secreted by the stranger; they are no longer distinguishable as human beings.

The gangridrene is non-grouping, but does approach others of its strain that it encounters on its travels. When two gangridrene meet, the older tends to place its hand upon the forehead of the younger, an action which leaves behind a black handprint that fades away within several seconds. Individuals sometimes lick each other's heads, as well, the wet slopping sounds filling the air around them.

Unlike many other predatory strangers, the gangridrene is rather amicable, and does not fight over corpses. Instead, the larger of the two tends to claim the corpse, with the smaller nodding and continuing on its own way.

Although the gangridrene's flesh-rotting effect is most pronounced in corpses, it does affect living sensitives, as well. Sensitives first notice this effect around cuts or abrasions, which grow dark and mottled before the flesh decays outright. Even wound-free sensitives, however, experience a dark patchwork effect on their skin, which spreads and grows necrotic as exposure continues. It takes approximately twelve minutes for an otherwise healthy sensitive to develop dangerous injuries in the gangridrene's presence, and forty minutes for these wounds to spread to a fatal degree.

Once it captures a sensitive, it places them inside its mouth. Although this, in and of itself, is not immediately fatal, sensitives who find themselves unable to escape decay alive over the span of several hours. Ultimately, however, this proves fatal for the gangridrene, as well, as the corpses of devoured sensitives are converted not to clear gelatin, but to a thick, corrosive black fluid. This "corrodorzian ooze" causes severe injuries (and often death) to the stranger, eating through the flesh in a bubbling, crinkling ripple. The affected gangridrene cries to itself in plaintive echoes, but^ɬ aside from this dramatic behaviour, it continues to engage in its usual actions until its face softens and sloughs off.

The dead stranger collapses into a heap, and abruptly dissolves.^Ъ

An aging gangridrene's skin grows softer, its body becomes misshapen, and its flesh becomes riddled with wounds and sores. Its behaviour remains unchanged, but diminishes in strength and focus day-by-day, until it slows down and stops, like a toy running out of batteries. The corpse falls apart and decays into mushy grey chunks, which if left undisturbed, decrease in size over five to five hundred days, until they disappear. Although the presence of other gangridrene speeds up their decomposition, nearby individuals do not recognize the dead stranger as a corpse.