Prince Dedenne, I think I'll sleep already after 4 hours ;p.
Btw, I just aware I can't see my friend list early in the game. Will tell you when I'm able to trade with my friend. Just keep my items for now. THANKS!!
In X, I used my Master Ball on Mewtwo. Now that I've played Y, I'm saving the Master Ball for the possibility that one of the event legendaries isn't given to us in a Cherish Ball.
Or on a shiny Basculin. (Before it uses Final Gambit.)
Why don't you keep a Ghost-type Pokémon in your team to switch to while fishing? That way Final Gambit will fail and you can hang on to the Master Ball for something else.
Edit: Or does the Pokémon still faint without causing damage? Might be worth finding out first.
Edit2:
Bulbapedia said:
If Final Gambit doesn't hit the opponent due to missing, type immunity or Protect, then Final Gambit will fail and the user will not faint.