Horrorman debuted as a living skeleton mentor to Chibigon in the 1991 film *Soreike! Anpanman Tobe Tobe Chibigon*, later joining the main television series. He wears a tattered purple shirt featuring crossed bones on the chest, with protruding kneecaps, prominent cheekbones, and permanently exposed teeth. The crossed bones on his shirt detach to function as boomerang weapons.

Despite his eerie appearance, Horrorman embodies a happy-go-lucky yet clumsy demeanor. He strives to be kind and helpful but frequently offends others unintentionally due to social ineptitude. His deliberate attempts to scare people consistently fail, though accidental actions or misunderstandings often achieve that effect.

He cohabits with antagonist Baikinman and pursues an unreciprocated obsession with Dokeen, regularly gathering gifts to impress her. Though affiliated with Baikinman, Horrorman rarely commits to villainy, instead displaying misguided goodwill. Both Baikinman and Dokeen exploit his gullibility, such as tricking him into adopting a frightening clown identity ("Pierrotman") under false promises of popularity. This deception caused him distress until others reassured him of his inherent likability.

A 2007 short film introduced Horako, who claimed Horrorman was once a prince, though the narrative’s reliability is contested within the franchise. Beyond his 1991 mentorship role, canonical media provides no further origin details.

His evolution centers on self-acceptance: an episode saw him seek popularity through a "cool" transformation into Pierrotman. After initial rejection and manipulation, he reconciled with his identity upon realizing others valued him. He later voluntarily adopted the clown persona for lighthearted fun, balancing on a giant ball to engage positively with the community.

Horrorman appears in the 2022 film *Eiga Soreike! Anpanman Dororin to Bakeru Carnival*; documented materials indicate no unique developments or backstory expansions specific to this appearance.