The Detention Bog is a muggy place with the following features:
Endless Muck. The muddy, stagnant water is 2 feet deep unless otherwise specified and counts as difficult terrain. The small islands of land and pathways shown on the map are normal terrain.
Tree Stumps. Stumps protrude 5 feet above the surface of the water. Their slippery and unstable surfaces means that climbing onto a stump without falling requires a successful DC 15 Athletics check as part of the move.
Poor Visibility. Pervasive mist and drizzle reduce visibility to 30 feet.
Teeming Creatures. The bog is filled with animal life, much of it noisy and distracting. Perception checks are thus made with disadvantage in the bog.