This is the room in which you need to fall into to start and finish an alliance.
Please see the follow chart for a list of cave and what room you can fall into it from:
Rabbit
Hare Summit, Foraged Fields, Rabbit Hole
Horse
Hooved Sands , Island of Light
Ox
Ox Path, Sunset
Dog
Gnawed Bones, Run
Dragon
Jeweled Dragon, Dragon Death
Monkey
Monkey Wasteland , Monkey Divide
Pig
Clove Hill
Rat
Gnaw
Rooster
Angry Roost , Chicken Conquest
Sheep
Shadow Grove , Shepard's Nook
Snake
Final rest, Snake fileds
Tiger
Dark Pen