"Omanyte is one of the ancient and long-since-extinct Pokémon that have been regenerated from fossils by people. If attacked by an enemy, it withdraws itself inside its hard shell."
One of the most interesting aspects of the Pokemon world is their advancements in technology. For in the games, if you find a fossil of a long extinct Pokemon, you can have it be reborn and put into your party. Omanyte is the first Pokemon to have that classification, and in the original games, you get to choose whether you get it or its partner fossil.
Omanyte's Basic Attacks are Water Gun and Mud Shot, while its Special Attacks are Brine and Ancient Power.