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 Hinawizama Syndrome.