Computer viruses are an everyday pain in the arse for the majority of the computer-using world. Apart from those using Linux, we more or less all have to deal with malware at some point, but in 1988 it was all new and truly terrifying.
This "worm" attack was actually designed to be an educational tool -- its aim wasn't to damage or steal stuff, it just wanted to find out how big the Internet really was. Unfortunately, the Morris worm spread like wildfire and brought various computer networks to their knees, costing the Earth to remove from individual machines. This new, unprecedented threat basically left the uneducated mainstream media to label it as Armageddon.
I guess we can thank the malware's author, Robert Tappan Morris, for basically kicking off the modern security software industry we all know and love today. Viruses are "just a call away". Ironically, that's more true now with all these government cyber attacks than it ever was in 1988. [YouTube via Reddit via Gizmodo Australia]