The sondrideri /ˈsɔndɹɪdeɹɪ/ is a slender, pale-colored stranger characterized by the dead branches that grow upwards from its back. Its body is weighty in comparison to its slender legs, thin tail, and small hands,^凵 though not overly bulky. Its bodily temperature reflects ambient conditions. Notably, its supple hide can be torn apart with any deliberate clawing, though it does not bleed or emit vapor following such injury. Its chestnut-colored inner flesh below is evenly muscular, albeit with the similar lack of moisture as its skin. When placed upon the tongue, flesh from the centermost parts of the sondrideri dissolve into an amenable flavor, but more outward samplings, especially its skin, are dry and chalky in the mouth.

The sondrideri is highly flammable,^𐊙 and does not survive a freeze.^Ꮘ

Its voice goes fully unspoken.

The sondrideri appears during daytime (particularly on sunny mornings) in outdoor but enclosed locations, generating within the shade of porches, beneath balconies, or within the fenced-in seating areas of certain restaurants, where it grows from a series of fibers that reach upward and entwine to form the sondrideri's body.

It does not form near others of its kind.

Soft of skin and tender of heart, the sondrideri possesses a temperate and merciful disposition. It spends most of its life asleep, its hands tucked beneath its head and its tail forming a thin circle around its body. It appears to dream without contentment nor displeasure, and lets out an occasional sigh as it adjusts the position of its tail.

When at rest, branches grow upwards from a point just beneath the sondrideri's surface. These extensions grow at a rate of 13.4 inches per day, but, due to natural wear and tear, rarely emerge beyond three to five feet in length, and always stop growing once a height of 7.8 feet has been obtained. The branches resemble common deciduous tree types in the area, but are not alive. Each sondrideri grows only one type of tree. Breaking these branches does no harm to the sondrideri, and pulling them from the stranger's surface leaves behind only a small and shallow hole, which closes up without scarring after 10-16 seconds.

During the sondrideri's early life, it experiences a 10-16% increase in bodily mass, with no change in subsequent proportions, and only a slight slowing of movement upon reaching full size.

The sondrideri awakens from its naps with a stretching and a shivering from snout-to-nose, this stirring usually spurred on by changes in weather. Upon rising, the sondrideri tiptoes to a new location, its tail dragging on the ground behind it. Although roaming throughout its life, each sondrideri tends to stay within a territory one to three miles in diameter at the widest point, with irregular territories (usually much longer than they are wide^ፈ) being the norm.

The sondrideri shakes off its branches at some point before settling on a new area to sleep.

It is predominantly diurnal, and is either absent or dormant during nighttime hours. It appears to require light to subsist, and, after several days in darkness, grows weak and dies with a slight sigh.

Engaging in only fleeting interactions with others of its kind,^𐐓 the sondrideri cannot be considered social.

Upon encountering a resting sondrideri, a majority of sensitives (64-93% of individuals, varying between cities) appear compelled to leave small offerings of pebbles, twigs, branches, leaves, nuts, or other small, natural objects, which they gather from the closest available location and place in a circular formation around the indifferent sondrideri.

Unless jarred from these actions by an outside source, affected sensitives will continue to gather objects for hours, if not days at a time. If interrupted from these actions, however, an entranced sensitive will snap back to full awareness, returning to the last train of thought that they had before encountering the sondrideri, and with only minimal memory of the sondrideri's form.

In addition to behavioural effects, the sondrideri also causes specific allergic reactions to random substances over a period of weeks to years. These allergies can cause a multitude of inflammatory symptoms ranging from breathing problems, to swollen glands, to rashes upon the skin. One sensitive might develop an insensitivity to polyethylene terephthalate, while another might become allergic to wool. Some of these allergies, such as a reaction to salt or water, can prove fatal, although such elemental allergies are not typical. Although some sensitives may appear to leave an encounter with the sondrideri without developing an allergy, this is largely illusory since a variety of rare materials, such as pure uranium or lanthanum, may be designated as allergens.

When not at rest, the sondrideri has no effect on a sensitive's behaviour, and remains unmoved by their presence, save for a weak turn of the head or a brief inhalation.