Magikarp Abuses The Buddy System
To an untrained eye, magikarp might appear as one of the biggest annoyances in Pokemon GO. How can it be anything else with a price tag of evolving into gyarados at 400 Magikarp Candy, right? However, much like how bothersome pidgey can appear to be, Magikarp is a very important Pokemon in Pokemon GO. To start, even with such a hefty cost, Magikarp still evolves into Gyarados. And as of the last update to Combat Power in Pokemon GO, Gyarados can reach a Max CP of over 3200, currently one of the highest in the entire game.
But the true greatness of magikarp does not just rely solely upon its evolution, but rather its niche in the buddy System. Unlike so many other Pokemon, Magikarp (as well as gyarados) only needs to be walked 1km as your Buddy Pokemon to receive each new Magikarp Candy. Suddenly, the 400 Candy needed to evolve into Gyarados doe not seem so farfetched!
But it does not stop there! After earning enough Candy to evolve into gyarados from the buddy System, Wild Encounters and rare Candies (obtained from raid battles), Gyarados still only needs to be walked 1km per Candy as your Buddy Pokemon (because of magikarp). So not only does the buddy system help players evolve their Magikarp into Gyarados, but they can also easily maximize the combat power of their newly acquired Gyarados by walking just a little further with them as their Buddy Pokémon.