Two-dimensional silhouettes of human form, blacker than the darkness around them, most often seen crossing doorways or standing in bedroom corners. They are the highest-volume report class in the archive.
Subtypes are stable across unrelated witnesses: the passing silhouette that crosses a hallway at walking pace; the watcher that stands at the bedside; and the Hat Man — a taller figure in a wide-brimmed hat and long coat, reported by witnesses on every continent, most of whom have never heard of him before their encounter.
Sleep researchers attribute bedside cases to hypnagogic hallucination, and the archive annotates accordingly. The waking-state hallway crossings, multi-witness sightings, and the global consistency of the Hat Man remain unexplained.