The bandoridroni /bænˈdɔːrɪdroʊni/ is a pale green and yellow stranger characterized by its constant forward growth. Its body is sludgy, while the arms are rubbery, and somewhat stretchy. The stranger constantly secretes a thin, clear-to-greenish liquid from its surface, and particularly from the eye markings, and excudes a fetid odor is so harsh as to make prolonged contact difficult to tolerate without appropriate protective measures. Physical contact with the stranger is similarly irritating,^Ⴣ and causes rashes and flaking of the skin, along with a swelling numbness within the muscle itself.

Though its body can be pulled apart with little effort, the bandoridroni can recover from wounds within seconds; even large holes and injuries do not pose a significant threat to the stranger, which is killed only when its cranial segment is destroyed. If divided in half, the front half reshapes itself where bisected, but otherwise remains unaffected by the dissolution of the body. Its flesh weighs (approximately) 178 pounds per every five feet of length.

The bandoridroni speaks through a happy, tootling sigh. Its voice is soft and high in pitch, but not childlike.

Mature bandoridroni grow forward at a constant rate of 0.2-18 inches per hour, with younger individuals advancing at a faster rate. Due to this continuous growth, a single individual can grow hundreds, if not thousands of feet long, although longer individuals do tend to degrade and fall apart at the tail end, preventing unlimited length.

Occasionally, the bandoridroni does seem to stir from its slumber to reach its arms towards certain objects, such as a discarded mascot character keychain, ripped sweater, or roll of duct tape, which it clutches closely to its side. These objects seem to comfort the stranger, whose lips curl up at the edges. The strain is primarily drawn to objects left behind accidentally, versus those deliberately placed or abandoned, with softer objects, such as a couch cushion, or stuffed animal, drawing a stronger response than hard objects, such as bricks, or metal ammunition boxes.

The bandoridroni's reaction to a sensitive is negligible, but specific. It grows towards the closest sensitive whenever possible, and exhales a happy sigh when touched. Though it whimpers in distress when burnt or attacked, it otherwise remains unable to resist, and after several minutes, seems to grow bored – it returns to sleep, and cannot be awoken again for up to ten days.

The bandoridroni be considered dangerous due to the highly noxious, toxic gas that it generates as a by-product of its growth. This gas, when not outwardly dissipated from the skin in minor expulsions, becomes enclosed in small cavities inside the bandoridroni's flesh, with impacts causing these pockets to burst open.

This gas is pale green in color, and possesses a faint, almond-like odor. Small amounts, such as the quantities exuded from the bandoridroni's surface, cause only vague drowsiness, a watering of the eyes, and an aggravation of the nasal passages. Concentrated pockets of the gas, however, are more potent – internal bleeding, organ rupture, and utter sedation set in within the first seventeen breaths.

A victim of the gas drifts off to sleep just before the more violent side effects occur.

The bandoridroni's growth loops back towards the sensitive's body, until it comes to rest atop the corpse. This is the only time that its forward growth ceases, as the bandoridroni awakens to sing a joyful melody, to which nearby individuals join in, as well. It remains at rest until the sensitive's identity is no longer visibly identifiable, at which point the bandoridroni falls back into somnolence, and continues to grow forward.

As the bandoridroni nears the end of its natural lifespan, its body loses strength and structure at a rapid rate. Its flesh collapses and bubbles, and its arms melt off. While most bandoridroni remain unresponsive to this degradation, a small number emit a quiet but distressed tone in anticipation of their imminent denouement.