human
Please generate a brief description of a gully in an unexplored wilderness forest with a trunk, a caterpillar, and pebbles.
assistant
There is a slight bend to the gully as it curves around the slope to the west. This seems to be an old streambed, still lined in water-tumbled pebbles and patches of dry moss. A velvety green caterpillar is working its way up a mottled, shaggy trunk, searching for the simplest path to its unknown goal.