Pikachu

The poster child of the Pokemon franchise is, quite disappointingly, not as great on the battlefield as Ash makes it out to be. While in the anime Pikachu is able to withstand assaults from the mighty Dragonite and electrocute even the ferocious Rhydon (aim for the horn!), Pikachu would be lucky to withstand a rain-boosted Surf from Luvdisc in the real game. Pikachu does wield a lot of power while holding a Light Ball, and has quite the extensive movepool, but that power is easily mitigated by its rice paper-thin defenses and sub-par Speed. Using Pikachu demands an incredible amount of prediction, skill, and some serious cojones. Fortunately there is quite honestly nothing more satisfying than destroying your opponent with the annoying rodent.