- "Darwin IV's only "sea" is really more a desert in the traditional sense; a place of little precipitation, harsh and inhospitable."
- ―Wayne Barlowe
The Amoebic Sea is a vast, gelatinous superorganism blanketing about 5% of the surface of planet Darwin IV. With an overall profundity of ten meters, the Amoebic Sea is the largest single colony organism known.
Located mainly on the northern hemisphere, the "sea" is composed of billions of single-celled organisms. Although the sea matrix is eaten by many kinds of faunal organisms (living both on the sea and the coast), the Amoebic Sea is also a predator itself, being able to extend long tentacles out of its surface and capture small flying organisms to eat. It is also assumed that when a creature dies in the sea, it soon becomes food to the superorganism.
The planet of Darwin IV once had grand oceans, but its water slowly evaporated over the eons, leading to the evolution of the Amoebic Sea, which is able to retain water within itself. All the water absorbed by the "sea" is sealed within the gelatinous matrix in order to prevent evaporation. Nowadays, Darwin IV has no large body of water, and most of the planet's water is found in the atmosphere, in the polar caps, or in the bodies of living creatures.
The "sea" is also home to a variety of organisms, the most famous of which is the gargantuan biped known as the Emperor Sea Strider. This 180 meter tall creature has two mouths, one on each foot. As the Sea Strider walks slowly on the surface of the Amoebic Sea; at the same time it feeds upon the gel. It is thanks to the shock absorbing, weight distributing, jelly-like substance, that the beast is able to grow to such a huge size. Among the other, much smaller inhabitants of the "sea" are flying creatures like the Diskflyers, the Stripewings and the Sea Strider's nymphs. There is also a large number of poorly known, symbiotic organisms living beneath the surface, within the gel.