Luxbush

A dense, dark-leafed shrub native to The Dark Forest and its borders. The Luxbush is antiphototropic: it grows away from light rather than toward it. Left in darkness it swells into a thick, thorn-knuckled mass that chokes gaps, corridors, and cave mouths. Exposed to Lux, its light-reactive sap drains from the branches and the whole growth withdraws downward, folding into itself and retreating into its own root-mass until the way is clear.

The retreat is not permanent. As the light fades the sap returns and the bush swells back into place, so a lit Luxbush is a closing window rather than an open door: Moonhead must move through the gap while it lasts. Chaining several bushes against a fading light is the region's signature crossing.