SimCity 4: Rush Hour/New Disasters

Autosaurus Wrecks
Autosaurus Wrecks is a dinosour-like robot that can cause caos in your city. Once you have chosen that disaster, click on a spot in your city, and he will appear. Click and drag the mouse to move him around, and he will demolish anything that comes through his path. He will disappear if he touches water.

Alien Attack
Click on a spot in your city, and shortly a giant UFO will appear above the selected ground. Then, lots of mini UFO's will come out and start to stoot lasers all over the place. The small UFO's can be controlled by clicking and dragging the mouse to the desired location. After a while, the giant UFO will send down a giant laser, destructing a large amount of your city, and then fly off. You'll be left with a deep whole in the ground and a big gap in your city.