Helgrub

You are one among billions of writhing maggots squirming through the cesspit. You think you are doomed to this for eternity until you witness one particularly fat grub devour another and slowly cocoon itself. As days pass you return to the cocoon seeing the shape of the being inside changing. Limbs! Pincers! It's not much. This new thing is still a mote compared to the demon lords above, but it's a way up and maybe beyond the vile muck.