Disclaimer: What? Pokemon belongs to Nintendo? Oh darn.
A/N: The Boso Peninsula is a real place in Japan, in the (guess what) Kanto region.
I combined the Omastar and Omanyte chapters.
Common Name: Omanyte, Omnite (juvenile) Omastar, Omstar (adult)
Scientific Name: Deminautilus megoculi
Description: Omastar is a large molluscan pokemon, adorned with a hard, 31-inch long spiral shell. This shell is off-white in color with clear growth rings and many spines along the shell's whorls. The soft inner body of the Omastar is light blue in color, with four thick, stubby tentacles surrounding its mouth and eyes. Six additional longer and thinner tentacles grow out from underneath the shell. Omastar's mouth is a beak with four mandibles, coming together to form an X-shaped bite. It is set in the center of the tentacles. Omastar's eyes are yellow with vertical pupils, and face forward. They move on their 'foot,' a powerful muscle that lies along their belly.
As juveniles, Omanyte are much smaller pokemon. Ten stubby blue tentacles poke out of a coiled, off white shell, measuring 16 inches long. Their eyes are large and white, with round pupils. Their gill siphon, which they use for jet propulsion, is usually concealed by the shell, but sometimes projects out.
Range: Omastar are known from only a few sites off the coast of the Boso Peninsula.
Habitat: Omastar live in at least 1000 feet of water, on the abyssal plain of the sea floor. Their habitat is a 'twilight zone' where there is too little light for a human to see, but more than enough for the Omastar's huge eyes.
Omanyte live in deep midwater (over 600 feet down), far from the surface and far from the bottom.
Call: Omastar are silent.
Diet: Omanyte shells are full of air pockets, which they use to maintain buoyancy at the correct depth. Due to this ability, they are able to migrate to the surface and back at night, hunting small invertebrates. They catch their prey with their tentacles, and crunch them with their beak.
As adults, Omastar are hunters of immobile creatures, dragging their six long tentacles in the sand for invertebrates. But sometimes, they take larger prey.
For many years, X-shaped scars on the shells of Cloyster suggested that Omastar hunted them, but until recently this had not been confirmed. It is now known that Omastar hunt deep-sea Cloyster, grasping them and holding them in place with their tentacles before chewing a hole in their shells, a process that takes hours. The Cloyster will struggle fiercely, and the Omastar must hang on tightly to the water-jetting bivalve or risk being stabbed with the prey pokemon's spines. However, one Cloyster provides food for weeks.
Life Cycle: Very little is known about Omastar breeding behavior in the wild, but in captivity they follow each other's mucus trails before mating, a squishy affair involving many tentacles getting in the way.
Omastar cast their eggs into the current as plankton. Their larvae do not have shells, but soon develop into miniature Omanyte. They grow slowly, and make a new growth layer on their shells each year. When they become Omastar, they grow spikes, and old spikes on the bottom wear off. By counting the spines and growth rings, scientists have determined that Omastar can live 70 years, and possibly more!
Relationship with Humans: Due to the difficulty of reaching Omastar in their natural habitat, few of these pokemon live in captivity. The few live specimens taken by submersible are under scientific study, but they may be trained like other pokemon. Their abundance is unknown.
Naturalist's Notes: The Omastar's shell holds its organs, as well as gas pockets that allow them to swim freely as Omanyte. However, as adults, their shell becomes too heavy for swimming, and they settle on the ocean floor.
When threatened, Omastar will withdraw their foot and smaller tentacles into their shell, and use their four larger tentacles to cover their face. Their spiked shell provides most of the protection they need, but if an attacker won't go away, they will actually use the shell as a weapon, rearing up and smacking the predator with it. They are also capable of spraying water from their siphon, and have been seen sucking up mud, which they then squirt in an attempt to blind their attacker.
Due to these defenses, Omastar's only real predators are Gorebyss, which can insert their proboscises into the armored mollusks' shells.
Omastar are believed to be a species that has remained unchanged for hundreds of millions of years. They are thus considered a 'living fossil,' and fossils similar to Omastar are routinely unearthed in Sinnoh, which has led scientists to believe that the region once lay underwater.