Bogiwan ga, Kuru

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)