Magikarps

right|300px
Magikarps are highly common orange-scaled carpfishes which can adapt to live in any body of water (aside from Unova). They are greatly beloved and adored by many for their childlike qualities. Nonetheless, transforming someone into a Magikarp or calling someone a Magikarp is a grave insult on Route 50.
It is theorized by some that Magikarps contain immense untapped potential, particularly due to their evolution into the mighty Gyarados. Such theories state that Magikarps truly are "magic carps", and may wield a vast arsenal of arcane magical talents.
Many Kanto and Johto trainers have succesfully defeated countless Magikarp on the sea route to Cianwood City, on fishing bridges, and the Lake of Rage north of Mahogany Town. However, this could all be an act to fool mankind, as the "magic carps" could possibly be letting their guard down by facing extremely inferior Pokemon and subsequently feign fainting.
Due to their widespread global population and their ease with adaptability, it is suspected that Magikarps may be the cause of everything and anything that occurs in the world, and that the Earth itself is secretly controlled by a universal cult of Magikarps. Karpkarp.
*Kamori, a character from PttR that did not make it to the end, was addicted to eating Magikarps.
*In LotE, Insyte jokingly "blames" Magikarps for Slick's team splitting up.
*To date, no RP character has ever been a Magikarp (to anyone's knowledge)