Omastar

Omastar (Japanese: オムスター Omusutaa) is a Rock/Water-type Fossil Pokémon introduced in Generation I. It is Kabutops's counterpart.

https://vignette.wikia.nocookie.net/pokemon/images/4/43/139Omastar.png/revision/latest?cb=20140328210735

Physiology
Omastar looks a lot like a Nautilus, a prehistoric creature related to squids. Omastar has a spiked spiral shell, which is heavy enough that it is hard for Omastar to swim. It has eight blue tentacles all over its body. Omastar also has a mouth that has two pairs of mandibles. It has yellow eyes with a slight black split pupil. Its face resembles that of a seastar, except for that the top of the star is cut off by the spiral shell.

Evolution
Omastar is the evolved form of Omanyte as of level 40.

Trivia
Omastar is the only Fossil Pokémon whose extinction has been explained: its shell was too heavy for it to move, leading it to die out from starvation.
 * In early English-language promotional material for Pokémon Red and Blue, Omastar was originally known as "Kargo". This name is derived from "escargot" (French for snail).
 * This explanation may also refer to the giant orthocone, ancestor to the modern octopus. The orthocone resembled a slow, cumbersome octopus with a long, pointed shell.

Origin
Omastar appears to be based on a type of Michelinoceras. In addition, its method of grabbing prey and cracking their shells with ring-shaped mouths may be based on Anomalocaris.

Name origin
Omastar's name is a combination of its Japanese name, a phonetic anagram of ammonite, and star (based on its body shape).

Omstar is a combination of オウムガイ ōmugai (nautilus) and star.