Kingdra, the Dragon Pokémon. Normally at rest on the ocean floor, but in theories of high activity, even a yawn has enough power to create whirlpools.
– Ash’s Pokedex
Kingdra’s type Water/Dragon makes it only have one weakness to Dragon. It’s also the only non-legendary Dragon type not weak to Ice. Plus, its ability Swift Swim (which makes speed double in rain), makes it a good member on a rain team.
My Kingdra is on my double battle rain team. Her name is Queendra, and she’s pretty awesome. She’s Adamant, and has Substitute, Waterfall, Outrage and Dragon Dance, and holds a Lum Berry. She’s paired up with Politoed with Drizzle, so her Swift Swim ability kicks in when the battle starts, and she can outspeed most Pokemon and makes a pretty good sweeper. The only downside I found was that you can’t specify a target for Outrage, so in the double battle, it randomly chooses a target, and it’s not always the target I want her to hit.
Stat-wise, it’s stats are pretty even, with Attack, Sp Attack, Def and Sp Def all at 95, which makes it versatile (can make it a mixed attacker or a sweeper of physical or special), though its moveset is rather limited