It seems to be based on a type of ammonite.
Omastar’s name is a combination of 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.
No: 139
English Name: Omastar
Japanese Name: Omusuta
Generation: 1
Type: Rock, Water
Species: Spiral Pokémon
Abilities: Shell Armor, Swift Swim, Weak Armor (hidden ability)
Evolution: Omanyte > Omastar
Omastar is a sky-blue ammonite Pokémon, with several tentacles and a pale yellow, helix spiraled shell on its back. Several sharp spikes line the shell’s midsection, spanning from its forefront to just a little towards its back. Its shell constantly grows, getting heavier over time and thus limiting its mobility. It is the weight of the shell that is most often cited as the cause for Omastar’s extinction. The shell’s hem has two circular indents where Omastar’s eyes come out. Its eyes have yellow sclerae and vertically-slit pupils. It has an oval mouth with a four-way jawed, fang-like beak. Once caught, it never lets go of prey, immediately biting down on its victim with immense power.
Before its own shell led to its extinction, Omastar swam the seas in search of prey. Even the hard shells of prehistoric Shellder stood no match to Omastar’s deadly powerful bite, and were quickly made a meal of by having their insides sucked out.
POKEDEX ENTRIES
Pokemon Red: A prehistoric Pokémon that died out when its heavy shell made it impossible to catch prey.
Pokemon Blue: A prehistoric Pokémon that died out when its heavy shell made it impossible to catch prey.
Pokemon Yellow: Sharp beaks ring its mouth. Its shell was too big for it to move freely, so it became extinct.
Pokemon Stadium: Attacks by ensnaring its enemy with its tentacles and biting with sharp fangs. Its overly-large shell makes it sluggish.
Pokemon Gold: Apparently, it cracked Shellder’s shell with its sharp fangs and sucked out the insides.
Pokemon Silver: Once wrapped around its prey, it never lets go. It eats the prey by tearing at it with sharp fangs.
Pokemon Crystal: Its heavy shell allowed it to reach only nearby food. This could be the reason it is extinct.
Pokemon Stadium 2: Apparently, it cracked Shellder’s shell with its sharp fangs and sucked out the insides.
Pokemon Ruby: Omastar uses its tentacles to capture its prey. It is believed to have become extinct because its shell grew too large and heavy, causing its movements to become too slow and ponderous.
Pokemon Sapphire: Omastar uses its tentacles to capture its prey. It is believed to have become extinct because its shell grew too large and heavy, causing its movements to become too slow and ponderous.
Pokemon Emerald: An Omastar uses its tentacles to capture its prey. It is believed to have become extinct because its shell grew too large, making its movements slow and ponderous.
Pokemon FireRed: Its tentacles are highly developed as if they are hands and feet. As soon as it ensnares prey, it bites.
Pokemon LeafGreen: Despite having strong fangs and tentacles, it went extinct when its heavy shell made it unable to catch prey.
Pokemon Diamond: It is thought that this Pokémon became extinct because its spiral shell grew too large.
Pokemon Pearl: It is thought that this Pokémon became extinct because its spiral shell grew too large.
Pokemon Platinum: It is thought that this Pokémon became extinct because its spiral shell grew too large.
Pokemon HeartGold: Apparently, it cracked Shellder’s shell with its sharp fangs and sucked out the insides.
Pokemon SoulSilver: Once wrapped around its prey, it never lets go. It eats the prey by tearing at it with sharp fangs.
Pokemon Black: It is thought that this Pokémon became extinct because its spiral shell grew too large.
Pokemon White: It is thought that this Pokémon became extinct because its spiral shell grew too large.
Pokemon Black 2: It is thought that this Pokémon became extinct because its spiral shell grew too large.
pokemon White 2: It is thought that this Pokémon became extinct because its spiral shell grew too large.
Pokemon X: Its tentacles are highly developed as if they are hands and feet. As soon as it ensnares prey, it bites.
Pokemon Y: Once wrapped around its prey, it never lets go. It eats the prey by tearing at it with sharp fangs.
Pokemon Omega Ruby: Omastar uses its tentacles to capture its prey. It is believed to have become extinct because its shell grew too large and heavy, causing its movements to become too slow and ponderous.
Pokemon Alpha Sapphire: Omastar uses its tentacles to capture its prey. It is believed to have become extinct because its shell grew too large and heavy, causing its movements to become too slow and ponderous.
Pokemon SUN:-
Pokemon MOON:-
