Have you ever heard of Stuxnet?
Stuxnet is a Microsoft Windows computer worm discovered in July 2010 that targets industrial software and equipment. While it is not the first time that crackers have targeted industrial systems, it is the first discovered malware that spies on and subverts industrial systems, and the first to include a programmable logic controller (PLC) rootkit.
This Wikipedia definition doesn’t do it justice.
What do you think about that?