As far as I can tell, the desert is made of bunnies. For example, look at this picture of the desert:

It looks basically bunny-free, but if you were to walk or drive through this scene, some of the landscape would turn into no less than 50 bunnies, who would then run a short distance, briefly looking like terrified bunnies, and then turn back into the landscape, like so:

It's seriously uncanny how invisible they are when they're holding still. Even when I've spotted them because they've moved, if I look away and then look back I usually can't find them again. But there are so many that I'm afraid of being quiet for fear of stepping on one.