We know its cry is an amalgamation of sounds as exotic as a New York cab's receipt machine (according to the Official LOST podcast) and various animal grunts and mechanical groans, but what is this vaporous beast that looks inside men’s souls?  Even though it took well into the second season for fans to accept it, the fact that the monster was merely an aggressive cloud of smoke was revealed in the season one finale, and only made the mystery all the more hazy.  (No pun intended.)