It is the titular main antagonist in Stephen King's 1986 horror novel It. The character is an ancient, shape-shifting, trans-dimensional evil entity who preys upon the children (and sometimes adults) of Derry, Maine, roughly every 27 years, using a variety of powers that include the ability to shapeshift, manipulate reality, and go unnoticed by adults. During the course of the story, It primarily appears in the form of Pennywise the Dancing Clown. "The Losers Club" becomes aware of Pennywise's presence after it kills Bill's little brother, Georgie. King stated in a 2013 interview that he came up with the idea for Pennywise after asking himself what children feared "more than anything else in the world", and feeling that the answer was clowns. King thought of a troll like the one in the children's tale "Three Billy Goats Gruff", though he imagined it living in a sewer system rather than under a bridge. The character was portrayed in its Pennywise form by Tim Curry in the 1990 television adaptation and by Bill Skarsgård in the 2017 film adaptation and its 2019 sequel It Chapter Two. Source: Wikipedia (en)