anaerobes. These unfortunate creatures were once top of the food chain until something green and slimy arrived and poisoned their atmosphere. Since that day, they have been condemned to live in dark, dirty places like the detrital ooze. A few manage to make their way up in the world but only as far as some animal's large intestine.
The SPA demands better conditions for these bottom dwellers, starting with the establishment of oxygen-free sanctuaries