There are five irreverently written religious “end of days” scenarios described at Exit Mundi, along with innumerable scientific speculations about how the world might end. They correspond to the eschatology (yes, I just wanted to use that word) of Christianity, Hinduism, Islam, Mayan beliefs, and Zoroastrianism.
I believe for some Muslims it is somewhat like the inverse of the rapture theory: Allah will call for his followers to murder anyone who isn’t a true Muslim, and after about 4-5 billion people are dead, the remainder will be in paradise (except, of course, for the remaining Muslim women).