Welcome to 1980s Bulgaria, a country on the brink of economic collapse and a hotbed of computer viruses. In an excerpt from his new book, Fancy Bear Goes Phishing: The Dark History of the Information Age, in Five Extraordinary Hacks, Scott J. Shapiro details the work of a notorious virus creator known only as the Dark Avenger, who wreaked havoc on computer systems because, well, he could:

Others had been pumping out viruses for months, but Dark Avenger built his to be lethal. His first creation would be known as Eddie. When a user ran a program infected with Eddie, the virus would not start by attacking other files. It would lurk in computer memory and hand back control to the original program. However, when a user loaded another program, skulking Eddie would spring into action and infect that program. These infected programs would be Eddie’s new carriers.

Eddie also packed a payload that slowly and silently destroyed every file it touched. When the infected program was run the 16th time, the virus overwrote a random section of the disk in the computer with its calling card: “Eddie lives … somewhere in time.” After enough of these indiscriminate changes, programs on the disk stopped loading.

Destructive viruses were not new. Vienna, for example, destroyed every eighth file. But Eddie was far more malicious. Because Eddie infections took a while to produce symptoms, users spread the virus and backed up contaminated files. When users discovered that their disk had turned into digital sawdust, they also learned that their backups were badly damaged. Dark Avenger had invented what are now called “data diddling” viruses — viruses that alter data in files.

Dark Avenger was proud of his cruel creation and claimed credit in the code. First, he inserted an ironic copyright notice: “This program was written in the city of Sofia (C) 1988–89 Dark Avenger.” The “Eddie lives” string that wreaked such destruction was a tribute to his love of heavy metal music. “Eddie” refers to the skeletal mascot of the band Iron Maiden; Somewhere in Time is the name of Iron Maiden’s sixth album, in which Eddie appears on the cover as a muscular cyborg in a Blade Runner setting, next to graffiti that reads “Eddie lives.”