You follow the southern tunnel branch. Rocky ground gives way to spongy earth rife with fungal growths. Some fuzzy patches of mold glow dimly, softly illuminating the tunnel. Other mushrooms grow round and squat, while others stand tall as men, gnarled and silent like ancient sentinels to this secret place.
As you move, soft whispers brush against the edges of your minds. It's not unlike Maude's rudimentary telepathic communication, but this is something more intelligent. There's no clear message though, just a presence. You know you're being watched.
The twisting tunnel widens and turns west, and is soon joined by a swiftly flowing underground stream of stinky water. You eventually emerge into a cavern lit by glowing fungi. The stream flows onto a rock shelf and over the edge into a pool about forty feet below. As you emerge from the tunnel and onto the shelf, the mind-whispers assail you with more urgency.
"Intruders. Surface dwellers."
"Unwelcome! Stop them!"
"Subdue them, put them with the other one."
"Let them be. Perhaps they will leave."
Look as hard as you might, you see no creatures that might be speaking to you or to each other. What do you do?