It appears in the form of a frightening man with a white face, eye make-up and red lipstick along with frizzy red hair and a clown costume which includes a red clown nose. I
It's true form is that of a large spiny deformed arachnid creature with two large yellow eyes with black round pothole pupils.
It is a primordial creature credited as the Eater of Worlds, Eater of Children and the Eternal Child in it's set.
It surfaces during a disaster in the small town of Derry. Maine to devour children.
It serves as the primary antagonist of the two part It Films just like it did in Stephen King's original novel apart from the Derry Bowers Gang led by Henry Bowers.
First Appearence - The Killing Of Lori Anne Winterberger
The It creature first appears in the first part of the two films at the very beginning seen stowed away in the closeline of the residence of a young mother and her daughter.
He advances on the daughter upon saying hello to her brutally ripping apart and devouring her leaving not much left of her little body.
He leaves behind as he departs a picture of George Denbrough which leads onto the flashbacks of the 60's Loser Club kids from Derry, Maine whom battled back against them in the time of his rising in that decade.
60's Attacks- The Takings of George Denbrough, Thelma Daniels, Nathaniel Carter, Vicky Burroughs
Over the course of the now adult Loser Club kids introductions flashbacks of the 60's ordeals begins taking up the first film's story which involves much of the It creature attacking them to which it takes basically only the form of a 1900 murderer clown man named Pennywise.