The Tornadotron was an insanely powerful Saucer Weapon in Destroy All Humans! Path of the Furon. A unique feature was the ability to use it while the Saucer was Cloaked, as stated by Orthopox as an act of God. While even the non-upgraded Tornadotron destroyed about 2 - 3 buildings, a fully upgraded one destroyed an entire town. You held down the fire button and steered the tornado into crowded areas or buildings.
The upgrades were the Tornado's Duration (time active) and tornado's intensity (power and destruction).