The tsinidrinzi /sɪnɪˈdrɪnzi/ is a warm-colored stranger with a rotund^ᶚ body, slender tail, and eight knobby and slightly uneven limbs. Its jaws are lined by a crowded row of jagged teeth, while its skin is smooth and vinyl-like over a body that is filled with a spongy, helium-filled tissue.

Though the stranger's highly durable and stretchy skin prevents incidental injury, it has almost no other defensive or regenerative abilities. Its foamy flesh, once punctured, deflates rapidly and fatally.

The tsinidrinzi talks in a fleeting, murmuring stream that sounds like a crowd of people whispering on top of one another, the individual words impossible to discern. The range of voices vary; some tsinidrinzi speak in the murmuring tones of impatient adults, while others sound like a multitude of children. Most tsinidrinzi's voices express a range of individual voices, with more uniform streams being the outliers.

The tsinidrinzi appears in any long, outdoor corridor, most often during overcast or foggy morning weather. Alleyways, covered bridges, and isolated side streets are common locations for a tsinidrinzi to generate, as are waterless canals, and highway underpasses.

When it first appears, the tsinidrinzi starts off as a small, bulging mass of rubbery flesh. This bundle unfolds itself in a series of bulges and swelled. Once its body has expanded to full size, the mature tsinidrinzi staggers unsteadily at first, but soon settles into its normal behaviour.

The strain's generation tends to occur in sudden bursts,^Ⴞ with several hundred tsinidrini appearing in various locations on the outskirts of a city.

The tsinidrinzi possesses an erratic, droll nature. When it is by itself, it races through its environment at random, its movements ranging from wobbling sways to jittery steps. It is neither particularly investigatory, nor specifically destructive; it climbs over dumpsters, rolls on the ground, and pulls posters off the wall and towards itself with no apparent greater purpose, and with no prolonged focus. It seems to show only loose understanding of its boundaries, and may even attempt to dart through fire, walk off of high ledges, or tumble into piercing obstacles.

When by itself, it does not talk.

The tsinidrinzi displays a fundamental magnetism towards others of its strain, and when two individuals meet, they remain together. As individual tsinidrinzi converge, their behaviour grows more focused,^ᶐ and their paths more straightforward. They begin to speak to one another, with each tsinidrinzi's whispering, murmuring voice mixing with the susurrations of its companions.

The masses of tsinidrinzi, once large enough, circle and converge upon a single, prominent landmark; most often, an extrusive fountain, statue, tower, or other visible marker.

Although the tsinidrinzi is theoretically harmless, it cannot be approached, for any proximity to it causes light-headedness and momentary confusion, forcing the sensitive to (often involuntarily) turn around and walk back in the direction from which they came. This effect, though unpleasant, does not^Ϡ cause any long-term damage. In the days following such an encounter, however, sensitives do experience a vague unfamiliarity towards their immediate surroundings, and must pay close attention to maps or landmarks to navigate even otherwise familiar environments.

As it ages, the tsinidrinzi sags and "deflates", and it loses its ability to remain with its companions. It continues as though dazes and unaware of its droop, before it suddenly crumples to the ground. Its once-elastic empty skin shrinks down into a tightened mass of wrinkles, and then to nothing at all.

If a tsinidrinzi is able to reach the endpoint of the teeming crowd's convergent journey, however, its body fades into an ethereal and vaporous form upon striking one of the destination's solid planes.