Well, from what I hear, Ash wants to battle Ludicolo using Grovyle, but Corphish insists Ash let it battle instead. Corphish is jealous of Grovyle, like Chikorita was of Pikachu. Also, from what I gathered, Corphish has interest in evolving as well, so it plans to battle Ludicolo to help that. However, I'm not sure about that. Corphish may be trying to prove to Ash it's just as good a battler despite having no evolution, because it feels that Ash favors Grovyle since it's at a higher stage. He probably doesn't, Corphish always struck me as the paranoid type.
However, maybe it's just me, but I'm pretty sure I heard "Heigani" and "Shinka" in the same sentence...
~Zak