A dense underwater kelp forest swaying in the current, with fish silhouettes drifting through dappled light shafts. Each frond is a tapered ribbon mesh whose vertices are displaced entirely in a vertex shader: sway amplitude grows toward the tip while root vertices stay pinned, and a primary current wave is layered with a faster secondary "flutter" wave for organic underwater fluid motion. Fish use simple orbit-plus-noise wander paths with a sinusoidal z-rotation to fake body undulation, and crepuscular light shafts are additive-blended cones whose opacity shimmers over time.