Ok, here is my crackpot theory concering the X:

Let's start, TOWTM tends to have a rather mobile lifestyle. Therefor, he has got a Macbook Air - which was introduced on January 15 2008 - just a couple of months prior to the events of z-day.

Well, it runs



Mac OS X. Striking symbolism, guys, hmm?!

Its hybrid kernel is partly based on BSD UNIX code. One of the main developers of BSD UNIX was Billy Joy who wrote Why the Future Doesn't Need Us, in which he cites a scenario by Frank Herbert in order to address the "a potential nightmare scenario, in which a mad scientist creates a virus capable of wiping out humanity."

Joy knew that nobody would believe him unless he would provide a prove of concept. He therefor deliberately caused z-day, shaved his head, got tattooed over his whole body, got a nice suit and started the extinction of humankind. However, due to his excessive comsumption of LSD during the wild 1970s, his intelligence unintendedly deteriorated whilst eating a crack head's brain. So he is therefor only capable of uttering a few words... poor guy.