A picture of a coastal piece of elalhtup. The dark area is where something is being digested.
Ehlalhtup is one of the largest organisms, if not the largest, ever to evolve in Obeidon. It is a single constantly-evolving sponge-like creature, that feeds off of anything that stays in contact with it for too long. It spans all of Ageriul's oceans, and means that its home has virtually no ecosystems at the bottom of the oceans, minus at vents. It has shaped the oceans of its home for millions of years, and has survived two mass extinctions, although in both it was reduced to a fraction of its ocean-spanning size. Estimates of its total biomass range from 50,000,000 tons to 13,000,000,000 tons, although the most commonly believed estimate is around 1,500,000,000 tons. Its sheer size gives it the nickname 'Kronos'.
Biology[]
Ehlalhtup can sustain such a large size over such long spaces mainly because of clever design. It can sense the amount of stress being put on it, and will compensate as needed. It can lighten parts of itself, either through eating itself or letting small parts of it rot to release gases, which the creature will then trap. It can trim or grow as needed, to maintain a healthy balance between support and weight. This animal is an eozooan, similar to a sponge or coral in behaviour. On the outside, a group of slime-mold-like cells are used to envelop potential food and digest it, before they pass the nutrients on to the massive central organism. They will stretch across the sponge's gaps like a near-invisible net, catching plankton and marine snow (dead plankton) as they fall from the surface waters. They also enable Ehlalhtup to trap larger animals or corpses, and drag them towards the main body of the sponge to be digested. This animal is so large, it's a biome in itself. It uses massive supports near the shore, and often grows closer in shore. If a chunk of the animal is attacked by a potentially lethal disease, or something else happens that makes a large amount of the organism cost more than its worth, it will block that piece off and let it sink to the bottom of the ocean. These flesh-falls are the cause of the only non-vent deep-sea ecosystems, which gives a sudden bonanza of food that passes by Ehlalhtup, until it regrows and blocks off the deep sea again.