Qwilfish (Japanese: ハリーセン Harysen) is a dual-type Water/Poison Pokémon introduced in Generation II.
It is not known to evolve into or from any other Pokémon.

Qwilfish is a sea dwelling Pokémon with a spherical body and a flat, paddle-shaped tail. The upper half of its body is dark teal and the lower half is very light yellow. Its tail is tall and thin with a dark teal outline, light yellow inside, and two dark teal dots in the center. Its eyes are even with its body and are always seen slanted angrily. Below its eyes are its puffy pink lips. All around its body are sharp, conical spikes, which evolved from scales over time. In order to attack, Qwilfish drinks over 2.6 gallons of water to inflate its body. It then uses the water pressure to shoot poisonous quills at its foe, which can cause fainting. Due to its round body, Qwilfish is not a great swimmer, and when filled with water it is even harder for it to swim.
(The above content is from the bulbapedia.)