Magikarp

Magikarp is one of the types of Pokémon species. The orange fish is considered by all to be the weakest of all the Pokémon, and has even been called "a pathetic excuse for a Pokémon" by the Pokédex. Their primary attack, Spash, does nothing what so ever, and it takes quite a long time until it can actualy learn a damage dealing attack, that sadly is not very effective. However, when Magikarp evolves, it evolves into a very powerful water and flying Pokémon Gyarados, a favorite among many.

Since it barely has any attacks, a common tactic to level it up is to give it an Exp. Share, which will give half of the experience points earned in battle to the Magikarp even if it never entered battle.