For in-game, Salazzle is a decent Pokemon that makes for a good Special Attacker if you lack one for your team.
It's ability Corrossion is great, but sadly is more useful in the metagame because stronger opponents use Full Restores.
Anyway, you should look for a female Salandit, as Kip said, and evolve it. Otherwise, it's not as useful.
Assuming you get a Salazzle, this is a good moveset:
- Flamethrower (Decent STAB)
- Venoshock --> Sludge Bomb (Same as above)
- Dragon Pulse (Neutral Coverage. Not great because of the Fairy Pokemon abundance, but you have Sludge Bomb for them)
- Toxic / Protect / Leech Life / Filler (It's ingame, and there are no HMs. Go crazy here, and pick whatever you want.)
I've not included EVs because in-game it doesn;t matter quite so much, but Speed and Special Attack are the only things worth investing in. Any ability as long as it doesn't hinder either of above mentioned stats is great, but look for a Modest or Timid natured one if you have the patience.
That said, a lot depends on the rest of your team, and you should really post that next time so it's easier to decide. For example, if you already have a strong Fire type Pokemon, or have your heart set on another Poison type, then it makes more sense to choose another Pokemon to counter specific trainers in game.