Poupelle emerges as a sentient life form spontaneously animated from landfill garbage on Halloween night. His entire body consists of scavenged refuse, featuring broken toys, an umbrella hat, a rusted jaw, and rubber hoses mimicking hair. His name directly reflects this origin, stemming from the French word "poubelle" (trash can).

Initially shy and bewildered upon gaining consciousness, he evolves toward optimism and kindness. He encounters the human child Lubicchi during Halloween, his appearance initially mistaken for a costume. After Lubicchi rescues him from near-incineration, a deep bond forms. Poupelle gradually assumes a protective, almost fatherly role for the child, partially filling the emotional void left by Lubicchi's deceased father.

Poupelle's core motivation kindles from his initial moments: discovering Lubicchi's lost bracelet—a vital memento of the child's father—within the landfill as he formed. This bracelet becomes physically embedded within his structure, impossible to extract without causing him damage. His unwavering commitment to safeguarding it underscores his devotion to Lubicchi.

His existence disrupts the norms of Chimney Town, where authorities perceive him and the very concept of a star-filled sky beyond the perpetual smog as dangerous. He actively supports Lubicchi's quest to prove the stars exist, culminating in their effort to detonate specialized explosives aboard a salvaged airship to disperse the obscuring smoke.

During the climactic airship sequence amidst turbulent weather, Poupelle disassembles. In his final moments before dissipation, he retrieves Lubicchi’s hat and successfully extracts the embedded bracelet, returning it to the child. His physical form disintegrates shortly after this act, coinciding with the temporary clearing of the smoke that reveals the stars.

A sequel titled "The Promised Clock Tower," announced for release in spring 2026, will continue the narrative universe. Specifics regarding Poupelle’s role or reappearance remain unspecified.