What would you do to the human race if you were an alien?

I'll turn earth into my idea of a perfect society and kill anyone who gets in my way.
...like an extraterrestrial Hitler that operates on a larger scale. (except I'm not after the Jews and won't set up concentration camps - just kill on the spot and dispose of the bodies in space)
...Then become the leader of this society where everything except crime will be allowed and 100% enforced.