You’ve been here long enough (how long?) that you can finally tell: something is wrong. The cavern walls are too close. The space that was once sprawling enough to contain cities is now claustrophobic.

At first, there didn’t seem to be anything living here. No animals, no foliage, just a vast wasteland of soft hills. Floating downwards, you’ve come to recognize the fauna and flora. Round creatures that float with you; spindly plants growing out of the rocks, probing the air; even the mountains and walls of this place are alive.

But now these creatures are dying. The things floating through the air are limp, corpses. The plants no longer reach and instead bend into themselves. The hills swell and the ceiling starts to buckle.