Existential threats to mankind
The greatest existential threat to mankind is, needless to say, existential philosophers. As a rule of thumb, the more impenetrable the writings of an existential philosopher, the greater the threat. Obscure Nazi existential philosopher Martin Heidegger wrote a book called "Being And Time", which was so dense and incomprehensible to the vast majority of humanity, that he had to write "On Being And Time" as a guide for how to read "Being And Time". It is said by some Pentacostal Christians that the delicious cool-ranch flavor captures the essence of a post-existential-apocalyptic world, with few survivors and fewer alcoholic Congressmen.
Transportation Security
According to Sonnyjim, the homeless on trains don't hold a candle in terms of security issues to existentialism. In fact, there was an issue some weeks back involving six Pakistani iron workers, an ounce of primo Kush and a temporary virgin shortage in heaven. Apparently, Osama Bin Laden demanded extra virgin rations for himself and his fellow masturbators killed in his palatial outhouse.
Those virgins that remained were rounded up for deportation to a temporary forward air base deep inside Ullalalooistan by greedy stippling peddlers. Revenge was swift in coming to those professors who refused to bow down to the power of Santa.
Black Market Racerats
Consequently, a black market in racing rats has sprung up in New Jersey. Animal rights activists have taken to crushing racing rats with Jersey barriers, thinking themselves clever, tongue in cheek. Still, dead is dead, and supporters of furry croupiers are doing themselves no favors. This sort of behavior is usually associated with fishmongers thumb, and other maladies of the work place.