A laptop infected with 6 of the most dangerous computer viruses in history was sold at auction to an anonymous buyer for $1.345 million - here's what each virus can do

"MyDoom" was a worm designed to leave infected computers open to other malware and viruses, according to a 2004 Cnet article. Computers would become infected when a user opened an attachment send in an email containing the MyDoom worm. Dong estimated "MyDoom"caused $38 billion in damages.

When it was first released, the "SoBig" worm and trojan virus "briefly brought freight and computer traffic in Washington, D.C. to a halt, grounded Air Canada and slowed down computer systems at many major companies such as advanced technology firm Lockheed Martin," according to a 2003 CNN article.

"SoBig" would be transmitted via email. Once the infected email was opened, it would scan the computer for other email address and spread itself further.

Dong estimates that "SoBig" caused $37 billion in damages.

"WannaCry" is a recent "cryptoworm" that acted as ransomware — where a user's data would be encrypted until the user paid a ransom to have their data released.

"The attack affected 200,000+ computers across 150 countries, and caused the NHS $100M in damages with further totals accumulating close to $4B," Dong said on the Persistence of Chaos website.

"DarkTequila" is malware that was prevalent in Latin America designed to collect a wide variety of data from an infected computer, including credentials to online services. That data could then be used for additional attacks, according to The Next Web.

Dong estimates it cost "millions in damages across many users."

"BlackEnergy" was originally intended as a data collection tool, but it evolved into malware that could damage a nation's critical infrastructure, according to Al Jazeera.

Dong said "BlackEnergy" was used used in a cyberattack "that prompted a large-scale blackout in Ukraine in December 2015."

You can read about the Ukraine blackout here.