The Tornadotron is an insanely powerful Saucer weapon in Destroy All Humans! Path of the Furon. A unique feature is being able to use it while cloaked, as stated by Pox as an act of God. While even the non upgraded one can destroy about 2 - 3 buildings, a fully upgraded one can destroy an entire town. you can hold down the fire button to steer the tornado into crowded areas or buildings.
The upgrades are the tornado's duration (time active) and tornado's intensity (power and destruction).