You grasp onto a large tree root to keep your balance and kneel down to look over the edge. You peer over...and are horrified! There is nothing over the edge--NOTHING! A great void that makes your head ache. You can see the earth underneath the trees going strait down, with all the different layers of ground and beyond that--a void!
Suddenly the ground rumbles and shakes. To your absolute horror you see the dirt being sucked out into the void, and feel your root being tugged on!