Croagunk, the Toxic Mouth Pokemon

Toxicroak has proven to be one of my best breeds for the Battle Subway, particularly because of his Dream World ability of Poison Touch. Here's how I work my Toxicroak;

Fake Out
Sucker Punch
Drain Punch
Dual Chop

IVs: 31 HP, 31 Attack, 31 Speed
EVs: 252 Attack, 252 Speed, 4 HP

Have him hold a King's Rock. That item combined with the Poison Touch ability lets each of his attacks have a chance to Poison and/or Flinch the opponent (30% chance to Poison, 10% to Flinch). Fake Out will Flinch regardless. Sucker Punch is there for priority, and you never know when you'll get lucky and get a life-saving Flinch from that. Dual Chop is a two-hit move, so you doubke your chances of getting the Poison and Flinch, plus it's a Dragon-type move, so it's only resisted by Steel (and Fairy in gen VI). Drain Punch is mostly for a strong Fighting STAB with dependable accuracy. He has other options, but I feel Drain Punch was the best all-around. You may prefer Cross Chop, Dynamic Punch, Brick Break, or Low Sweep, depending on your supporting team and personal preferences.

So how do you get this lovable trickster?

(1) Breed a female DW Croagunk with a male Mienfoo that knows Drain Punch and Fake Out.
(2) Aim for an Adamant Nature. Teach Dual Chop via a B2W2 move tutor. If you do not have access to B2W2, then go for Poison Jab for another STAB move with a high Poison chance.

This Toxicroak works wonders for me in single trains, essentially freezing the opponent with Flinches while the Poison dwindles their health. A great teammate for him would be Hydreigon or Honchkrow, as they are immune to two of Toxicroak's most common weaknesses (Ground and Psychic). This build also works great for double battles too, serving something of a support role by immobilizing one target so your partner can safely attack. Just avoid using him against Crobats, he has a hard time with those.

Brock out.