Bogiwan ga, Kuru

Overview

When he was a child, Hideki Tahara had a chance encounter with "Bogiwan," a monster feared by his late grandfather. Now that he is a working adult with a family, a formless visitor appears... When he is confronted by a junior coworker who loses his arm, uncanny phenomena at home, and unseen horrors, what he clings to is... (Source: Kadokawa, translated)

Source: AniList