Pennywise pretty much made Derry the perfect place for a creature like itself to live, and with the whole town under its control and with a lot of children (and adults) to feed from, IT didn't really have reasons to leave Derry.
Origin. Pennywise was one of the countless forms of an ancient dimensional entity that landed in what would become Derry, Maine millions of years later.
The evil hibernates for approximately 27 years before awakening, upon which time he begins stalking and killing victims, usually children. Each cycle is seemingly triggered by a significant tragedy or act of violence and ends the same way.
This creature feeds off fear and its preferred victims are children as their fears are simpler, but there might be another very different reason for that, and it's rooted on the real meaning of IT.
They reach the conclusion that Pennywise has all of the adults under some sort of spell that prohibits them from seeing him. The adults of Derry are shown to be villainous in their own right as well. The adults of Derry are shown to be true villains of the story in the same way as Pennywise.
Why Pennywise Chose to Stay In Derry Explained | IT: Chapter 2
What does Pennywise hate the most?
Stephen King's IT introduced readers to a one-of-a-kind creature that can take any form, the most common one being Pennywise the Dancing Clown, and as menacing as it is, this creature has one big enemy it's truly scared of: Maturin, the turtle.
Beverly's father can't see any of the blood in the bathroom. On one level, this is because he's an adult; a major theme of It is that the innate power of childhood and ability to remember childhood fears serve as a crucial weapon against It.
Georgie Elmer Denbrough is a fictional character created by Stephen King from his 1986 epic horror novel It. Georgie is the younger brother of Bill Denbrough, and falls prey to Pennywise the Clown. He is used by Pennywise to taunt Bill throughout the novel.
"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.
A common interpretation of this phrase is that it refers to where the souls of IT's victims go after they die, as they wouldn't go to heaven nor hell, staying instead in the “deadlights”, which would be a sort of limbo, thus “floating” in that middle point for eternity.
In the novel, it's explained that Pennywise targets children because their fears are less complex than those of adults, allowing It to easily take the shape of whatever its victim fears.
Pennywise had targeted Georgie when the boy was too young to know any better or fight back. In the clown's most contemptible murders, Pennywise did not rely on visions or fears to lure Georgie in; instead, Pennywise exploited Georgie's trust and turned it into a fatal weakness.
IT arrived on Earth through an event similar to an asteroid impact, landing in what would later become Derry, Maine. Once there, IT adopted its usual pattern of hibernation that lasted between 27 and 30 years, awakening to kill and eat and then going back to sleep.
One of the themes addressed in IT is trauma, and how the mind tends to lock those painful memories away as defense, which is what happened to the Losers when they left Derry for the first time.
After the grown-up Losers Club kills It in the second Ritual Of Chüd in 1985, a huge storm ensues, destroying many buildings and landmarks in Derry, including the Standpipe.
In the novel, It's origins are nebulous. He took the form of a clown most frequently, Mr. Bob Gray or Pennywise, but his true form is an ancient eldritch entity from another universe who landed in the town that would become Derry by way of an asteroid and first awoke in 1715.
Pennywise the Clown is not a clown at all. The Pennywise the clown origin story sees an ancient, evil being that is perhaps as old as the universe itself. In the novel, however, the entity IT/Pennywise has a real name — Bob Gray. Bob Gray isn't human, however, and shares the same origin as IT.
In their final battle, the Losers' Club was able to kill Pennywise by reducing him to a child-like form as they overcame their fears. In the moments before Pennywise died, his fear is reminiscent of Georgie's own, therefore closing the cyclical nature of Pennywise's murders. Georgie's death was unique in It.
A neighbor witnesses his disappearance, but the fact his body is never found gives Bill hope Georgie somehow survived. Pennywise prays on this in the film, using that hope to lure Bill in the finale. Bill later finds the tatters of Georgie's coat and finally accepts his brother is gone.
Luke Roessler portrays Dean, a young boy who meets Bill near the storm drain where Georgie was killed in 1988, and who is later killed by It at the Funland.
In the novel Georgie was left on the street to bleed to death while the full extent of his fate is fairly ambiguous in the miniseries, but here he's dragged screaming wholly into the sewer where we can assume Pennywise ate his physical body.
Despite her screams, her father is unable to see it, leaving Bev (and the Losers Club, depending on the version of the story) to clean it all up. And so the blood becomes a representation of the fear of her impending womanhood. To put it bluntly, the blood Bev sees is period blood.
When 'It' unleashes the copious amounts of blood through the sink plug-hole, the thick red liquid spraying the walls of her bathroom encompasses her fears concerning womanhood and her father's inability to see it denotes his male obliviousness as well as the emotional distance between him and his daughter.
But the focus is different: Beverly's It manifests as blood — buckets of blood that spew from the sink — and Fukunaga makes it clear that the blood is a metaphor for her own fears around growing up and becoming a “woman,” something she fears would make her more of a sexual object to men, including her father.
