Ludicolo

Ludicolo's unique Water / Grass typing and good special bulk allow it to check Kyogre extremely effectively; it is one of the few viable Pokemon that can safely switch into Kyogre's Water Spout multiple times, allowing the rest of your team to focus on checking other threats. In addition, its access to Leech Seed and Rain Dish makes it a massive pain to take down if rain is up and Ludicolo finds a turn to safely use Leech Seed. In conjunction with Substitute, Ludicolo is capable of stalling the foe with Substitute + Leech Seed + Protect for long periods of time. In a pinch, Ludicolo can even attempt to check Pokemon such as Palkia and support Groudon. However, Ludicolo is extremely physically frail, so even neutral attacks such as Giratina-O's Dragon Claw are capable of inflicting severe damage. Ludicolo also lacks many resistances, which limits the pool of Pokemon it can check, although the Water and Ground resistances are useful.