Parasect
HP: 60
Attack: 95
Defense: 80
Special Attack: 60
Special Defense: 80
Speed: 30
Attack: 95
Defense: 80
Special Attack: 60
Special Defense: 80
Speed: 30
Effect Spore: The opponent has a 10% chance of being induced by PARALYZE, POISON, or SLEEP when using an attack, that requires physical contact, against this Pokémon.
Dry Skin: HP is restored when hit by Water-type moves or when it is raining but also makes the Pokémon weak to Fire-type moves and reduces HP during strong sunlight.
Dream World Ability:
Damp: Explosion and Selfdestruct will not work while the Pokémon is in battle.
Double Battle:
(Doubles) Rain Counter
Parasect @ Focus Sash/Yache Berry
Adamant
Dry Skin
252 Atk, 252 HP, 4 Def
Spore
Seed Bomb
X-Scissor/Rage Powder
Protect
Parasect serves as a very good counter to rain with its amazing ability Dry Skin, allowing it to switch into Water moves, or just to put things to sleep. Seed Bomb is needed, as it is a useful STAB to have in this metagame, as it hits Politoad and Tyranitar, too very common rain setters. The choice between X-Scissor and Rage Powder is a choice of coverage and support. X-Scissor is generally the better choice, as it hits Psychic types like Cresselia and Ice types like Abomasnow, however, Rage Powder is unexpected and can occasionally save a game. Protect is a staple on most doubles pokemon, as it makes prediction easier.
Parasect is simply weak to some common types, such as Fire, Rock and Ice. That, and its incredibly slow speed means that it needs to either be under Trick Room, which is a decent idea, or it needs a Focus Sash. If Focus Sash is used on your team already, it should run Yache, as it appreciates being able to survive a Blizzard from Abomasnow and KO back with X-Scissor, or put it asleep. The EVs are simple, HP and Attack, as that is what Parasect needs to have.