The Brook Doll appears as a vintage porcelain figure with blonde hair now matted green with creek algae, wearing a perpetually dripping Victorian dress. Its cracked face bears an unnaturally expressive countenance, while bioluminescent eyes glow with supernatural green light that pierces through fog. The doll leaves wet footprints that never dry and seems to move when observed only peripherally, defying natural laws of physics.

Brook Doll serves as an early warning system for territorial breaches, floating downstream ahead of creature emergence events to herald supernatural disturbances. Its presence amplifies psychological tension by corrupting childhood safety symbols, making players question reality as the fog thickens and the boundary between natural and otherworldly dissolves.