Shellder

Description
This Pokemon's shell can withstand any attack. However, when it is open, the tender body is exposed. It swims facing backward by opening and closing its two-piece shell. It is surprisingly fast. Grains of sand trapped in its shells mix with its body fluids to form beautiful pearls. Clamping on to an opponent reveals its vulnerable parts, so it uses this move only as a last resort. At night, this Pokemon uses its broad tongue to burrow a hole in the seafloor sand and then sleep in it. While it is sleeping, Shellder closes its shell, but leaves its tongue hanging out.

Evolution
Shellder--->Water Stone--->Cloyster

Location
Cerulean Gym: Uncatchable