Wow, so I'm the first one.
Damp- Explosion and Selfdestruct will not work while the Pokémon is on the field. A rather useless ability. It is definately outclassed by it's other abilities. It can only ever be used situationally, and most of the time it will never do anything.
Cloud Nine- All weather effects are negated while the Pokémon is on the field. Also situational. However, it is more likely to have an effect, and can seriously mess up the opposing team.
Hidden Ability (Available):
Swift Swim- When rainy, The Pokémon’s Speed doubles. However, Speed will not double on the turn weather becomes Heavy Rain. This ability is probably better than it's other abilities. Unfortunately, it is one of the slower users of swift swim. It will still give Golduck a needed boost, as its stats are mediocre.
+Decent Special Attack stat
+Has a priority move
+Evolves from Psyduck
-Low overall stats
We bring the feast, just add rain!
Golduck @ Life Orb/Choice Specs/Damp Rock
Ability: Swift Swim
EVs: 252 Spd / 252 SAtk / 4 HP
- Aqua Jet/Mud Bomb
- Psyshock/Ice Beam
- Scald/Hydro Pump/Surf
- Simple Beam/Rain Dance/Ice Beam
Golduck has a good special moveset and it shows. It can run a Life Orb set that allows it to cripple other Pokemon with Scald and Simple Beam, while still attacking with priority and being able to attack special walls. It can go all attacking with a Choice Specs set, or it can even hold a Damp Rock and set up rain itself.
Cloud Nine, Soak, Calm Mind, a physical set
Double & Triple Battle Options
It knows Surf, Rain Dance, Dual Screens, and Wonder Room? It really doesn't have a good place here, but I suppose it could be used with a Water Absorber...
It's not too hard. Hit it with a super-effective move, or even a neutral STAB move, and it should be gone rather quickly.
There was something here. And then there wasn't. WHOOP DEE DO.