sends out Gengar
Focus energy isn't a very useful move since you could just attack in the turn you used it. Unless your strategy calls specifically for a critical hit, then I wouldn't go with it. Earthquake, while powerful, still fails when used against flying types or levitate users. This combo can do quite a bit of damage, but it's not the greatest combo ever, as it can still be countered by a fair amount of pokemon, many of whom are very common in the metagame.