What is "Stuxnet" and why it is considered the most lethal cyberweapon ever created?

The name "Stuxnet" is not theofficial name of this lethal virus and was given to it by the Kaspersky(Anti-virus) corporation, which first identified it in the eastern European country of Belarus. Stuxnet is believed to be the most devastating cyberweapon ever created in the short history of cyberspace. Antivirus corporation came to the conclusion that this virus is so sophisticated that it did not even have a single bug and every line of code, which were immense, was made to do something and targeted a special type of equipment rather than steal money or information. This could not be achieved by a corporation or a hacker group and thus resources needed to create such weapon could only be attained by a State. The special equipment that it targeted was a "PLC" which stands for the programmable logic unit which basically controls the tools in a industry.

As the malware targets a PLC, now the question was which type of PLC it targets and after doing some intensive research they came to the result that it didn't even target type of PLC rather a single PLC made by Siemens.This surprised and confused the investigators at Kaspersky and they didn't reach any conclusion. However when they put it the geopolitical aspect going at that time into the equation then mist started to condense and they started to understand the whole situation. At the same time news was coming from IAEA that Iranian nuclear project has taken a hit due to some mechanical failure. This news made investigators think that maybe this is somehow connected to all this. When they filtered the regions where the virus has taken its most toll, then they were sure as it was the Persian country of "IRAN".

Iran nuclear power plant at Natanz which was the prime facility to produce weapons-grade uranium was most hit because somehow centrifuges which contain the yellow cake as they call the "radioactive uranium" started rotating more than it should and started exploding one by one and took back the Iranian nuclear project by years.

The Stuxnet virus targeted the Siemens made PLC which controlled the movement of the centrifuges and made some of them rotate too fast and some too slow thus jeopardizing the whole process. The virus was jointly developed by US and Israel as a part of a campaign to hold Iran from getting nuclear weapons.US, which didn't had any offensive cyber wing even created a separate cyber organ called " US cyber command" which was sanctioned by the US govt to carry out such attacks, however, it is believed that most of the coding work was done by Israel.

However, the graveness of the situation was understood afterward when investigators came to know that the malware had even infected installations in the USand Homeland department was put on alert as even they didn't know about the Stuxnet project.

Stuxnet is considered the most sophisticated malware ever created just due to the mere scale of its effectiveness and it did not affect the software rather the PLC's which today controls almost every industrial and commercial installation like Power grids, Traffic lights, ATM and every piece of machinery that is connected to the internet.