Seaking

Seaking is one of the several Pokemon introduced in RBY that never saw the light of the upper tiers, always finding its home in NU. The goldfish with a horn was deemed as one without competitive value. Even the Magikarp that you catch with Old Rod evolves into the great and mighty Gyarados. It seems like this poor old fish will never make a name for itself; and that's probably true. There's nothing much to say about its horrible stats. 'Horrible' might not even be enough to describe Seaking's stats. It has only one stat that breaks past the base 90 bench mark, and that is its base 92 Attack, which is rather average. To add insult to the injuries, it has an incredibly shallow movepool, probably because it stayed in its tiny little fish pond for too long. Seaking isn't a very apt name; it isn't even close to the true King of the Seas known as Kyogre. In fact, it's the opposite; it is the Slave of the Seas, outclassed by almost all of the Water-types that have appeared throughout the generations. Fortunately, the change of move mechanics in DPP gave Seaking some use. Its main STAB attack, Waterfall, became a physical attack, giving Seaking some utility in DPP UU. BW gave another gift to the lonely goldfish in Lightning Rod through Dream World. With that, Seaking gained an immunity to Electric-type moves, meaning that it has only one weakness left. That said, there isn't much of a reason to use Seaking, even in NU. But if you need an Electric immune Pokemon that can use Water-type attacks, Seaking is probably what you're looking for. That's a really small niche, probably smaller than Seaking's supposed memory space.