The jellyback is a tall creature which feeds on the high fruits of certain trees. Once the creature reaches maturity it produces egg cysts within the large sac on its back. These eggs are very small, hard, and numerous. The timing of this is correlated with symbiotic flying creatures' breeding patterns. Once the flying creatures begin their courtship, the jellybacks begin a transformation. Toxins usually stored in their sacs become neutralized; in the process the sacs turn a bright red color as the creatures' limbs stiffen. The jellybacks die in this process, retaining a rigid standing position, and using the red color of the jellybacks' sacs as a signal that it is time, the symbiotic flying creatures tear into the sacs and feast on the mass stored therein. These nutrient-rich tissues and fluids give the flying creatures the energy they need to produce their young. The jellyback's egg cysts are also consumed incidentally, but are not harmed by the flying creatures' digestive processes; in fact the process is essential to allow them to hatch. The egg cysts are later deposited by the flying creatures as they excrete them far and wide. The cysts then hatch and, using the nutrients from the flying creatures' droppings, begin the first stage in their life cycle. The dead jellybacks' bodies can remain fixed in a standing position for years, providing structures for the flying creatures to build safe nests high above the plains.
Rising up through the fog in the distance, the fossilized remains of complex mega-structures formed over millions of years by long extinct burrowing tube worms have been exposed by geological processes to form dramatic arches looming over the plains.
To see an anatomical diagram of this creature see this illustration:[link]