Cables are aliens from another planet that use computers to reproduce.
Below is a quick list of a few important things I learned from the film that I never knew before, and a few lessons that were inferred from the plot. I wish to thank the creators of ID4 for making these facts much clearer to me. Aliens like to blow up significant land marks first. All pro-UFO people are morons who dance atop the building directly under the Death Ray. The Law of Averages says you'll survive the Death Ray.