A Bulgarian virus writer who seemed to have a personal dislike for Vesselin Bontchev, a Bulgarian anti-virus software writer. Dark Avenger’s claim to fame is the invention of polymorphic code—code that mutates while keeping the original algorithm intact. Rumor has it that the latter was invented in 1992 by Dark Avenger as a means to avoid pattern recognition from anti-virus software (that is, a program allowing users to scan files to locate and then get rid of computer viruses and other malicious software known as “malware”). Farlex, Inc. The Free Dictionary: Dark Avenger. Farlex, Inc. Website. http://encyclopedia.thefreedictionary.com/Dark%20Avenger.