Mystery Science Theater 3000, Season 1

Commando Cody:
Do you mind telling me why your men are carrying out that campaign of destruction on Earth?

Servo [as Retik]:
It's an election year.

Retik:
Not at all. They are merely softening up your defenses for our impending invasion.

Commando Cody:
Why do you want to invade the Earth?

Retik:
Because the atmosphere on the Moon has become so thin and dry, it is impossible for us to raise food, except in pressurized greenhouses.

Joel [as Cody]:
Get a humidifier!