Pokémon Challenge: A Man Beat Sun/Moon With Magikarp

Nanako used a few strategies, with the most interesting and elegant being explained by Rocket News 24 who translated the Twitter page. He would stock up on healing items, then keep healing his Magikarp until the enemy ran out of PP. The enemy would then struggle, which hurts itself as well as the player, until it eventually fainted. Yes, Nanako literally let his enemies beat themselves to death.