At night, a faint yet persistent vibration resonates within the wall. Could it be the humming of an HVAC unit, its airflow creating unsettling noises? Or perhaps, as some speculate, it’s a ghostly presence, its ethereal existence manifesting through unexplained sounds. Alternatively, natural phenomena like nocturnal animals or temperature fluctuations may be the culprit. Additional possibilities include plumbing issues, structural defects, or construction activities.