Shellos

Shellos is a decent tank in Little Cup, with good defensive stats and access to Recover boosting its longevity by leaps and bounds. Combine that with a wonderful ability in Storm Drain, which gives it an immunity as well as the potential to boost its more than useable Special Attack, and Shellos certainly can dish out hits as well as it can take them. Though one may assume at first glance that Slowpoke is superior due to Regenerator and better stats, Shellos can easily differentiate itself from its Water-type brethren. Shellos, unlike Slowpoke, is not weak to common Dark-type moves and U-turn, and has a great niche in Clear Smog, which removes the opponent's boosts while bypassing Taunt, allowing it to effectively counter a sizable number of threats in Little Cup.