Here's my prediction: you'll say you won't watch it, then you will, then you're totally going to regret it.
National Geographic has some footage of the inside of Gomantong Cave in Borneo, where the walls are caked with bat and bird guano.
Of course, bats and birds wouldn't stay there if the guano was just sitting there, piling up. The poo floor has created a whole ecological niche for scat-eating crawlers: cockroaches, grasshoppers, cave scorpions, mites, and a menagerie of others. The sheer number of cockroaches there have earned it the name "The Cockroach Cave."
And it's not just fecal matter these things are eating up. They even clean after bat corpses, stripping them down to bone in mere hours. Had enough internet for today? Me too.