tuxnet is a malicious computer worm, first uncovered in 2010, thought to have been in development since at least 2005.
tuxnet specifically targets programmable logic controllers which allow the automation of electromechanical processes such as those used to control machinery and industrial processes including centrifuges for separating nuclear material.
Exploiting four zero-day flaws, Stuxnet functions by targeting machines using the Microsoft Windows operating system and networks, then seeking out Siemens Step7 software. Stuxnet reportedly compromised Iranian PLCs, collecting information on industrial systems and causing the fast-spinning centrifuges to tear themselves apart.
No lines are longer than 80 characters, TYVM. Other specified properties aren't being scored automatically at this time so this is not necessarily good news...