Bug/Psychic
We all know that Psychic has been a risky typing post Gen 1, and with Pursuit around every corner, it's only getting more risky.
Add to that, Gen V has a huge amount of Fighting types (which are 4x resisted) who pack Rock moves (2x effective), and you have a great guessing game. Do you switch in the tank the resisted STAB? You might get hit by Stone Edge instead, and you're weak to SR while you're at it.
Plus, I'd love to see this thing go up against Terrakion. :)