It will cause the 2012 apocalypseIt's hibernation lasts roughly 27 years. The last time it woke up was in 1985 and It completely destroyed Derry. Now that King has revealed It's existence to the world, It will be forced to destroy the entire planet when It awakens in 2012 forcing humanity to start over so It can continue to exist in relative peace. At least until someone decides to write another book about It.
IT is a Youkai
IT was responsible for the Hinamizawa Syndrome.
It being a woman wasn't omitted in the movie.The "Kiss me fatboy" scene was just Foe Yay.
The true form of the Deadlights is...An innumerable number of "balloons" glowing with an orange light, floating endlessly. Within each balloon is the soul of one of the children that IT killed, causing them to float.