The scene where the sink starts spewing blood is horrifying and disgusting, and made even worse by the fact that the Beverly's dad doesn't even see the blood.
The shower scene in which Pennywise is shown calling out to Eddie from below one of the shower drains, lifts open the drain, sticks his hands out and basically shoves at the drain opening with his hands literally like it was clay to make it big enough so he can stick half of his body out and tell a horrified Eddie "Here I am, wheezy! Hey, you're gonna like it down here. Won't do any good to run, girly boy! See you in your dreams! Oh, come back anytime! Bring your friends!" No doubt it left kids with a paranoia fueled fear towards shower drains or probably drains of any kind.
Pennywise then abruptly lowers his head and lifts it, letting out an loud unearthly roar before chuckling and looking directly at the camera while some creepy music plays.
"Kill? <chuckle> ME? Oh, you are priceless, brat. I... am eternal, child. I am the Eater of Worlds - and of children. And YOU... are NEXT!"
Akin to the scene where blood comes out of the sink is the scene wherein Bill is looking at an old photo album of his dead brother George, and suddenly Georgie's picture winks at him. He throws it across the room and the album starts moving on its own, turning back to that same picture, which then starts to bleed heavily. Then when his parents come in and can't see the blood.
This line from Pennywise: "I'll kill you all! *laughs* I'll drive you crazy... and then I'LL KILL YOU ALL! I'm every nightmare you've ever had, I am your WORST DREAM COME TRUE! I'm everything you EVER were afraid of!"
The buildup to it: the kids find an old photograph with a familiar-looking figure in the background. And then it starts moving...
Tim Curry, in all that clown make-up as Pennywise. Even when he's not doing anything particularly frightening in the movie, he's still creepy as all hell. To give a good idea as to how creepy Pennywise is, the other actors/crew-members actually avoidedTim Curry while he in make-up and on set.
The scene where Ben has just confessed his love for Beverly and they kiss and embrace, only for him to look in the mirror and see that the person he is holding... is wearing a clown suit.
Eddie's encounter with Mr. Keene, and the idea that Keene's memory of Eddie was all fabricated by the Clown.
The idea that the adults can't see the blood and therefore cannot remove the blood until they wash the body part bloodied, means they could go up to a day without washing it off if it's on their faces, and hours if its on their hands...there could be phantom alien paint all over Bill Denborough's and Bev Marsh's houses.
One thing that stands out to many though is the dead boys in the water tower. Just the thought of falling into the water and having no way of getting out, just having to wait for death... Creepy beyond words.
How about the fact that Pennywise isn't confined simply to his own novel? He appears in several other Stephen King novels, and plays no direct role. He simply sits in the background, possibly waiting for something.
His cameo in Tommyknockers, he just stands down the street and waves.
Dreamcatcher. "Pennywise lives!" Oh, Jesus...
1958+27=1985 and then 1985+27=2012. If Pennywise is still alive, next year promise to be very interesting for the people of Derry ... and for Stephen King's readers...
Pennywise in the storm drain.
"Everything down here floats."
Patrick Hockstetter. An insane and unfathomably sadistic solipsist who believes that he was the only "real" being in the universe, and who had no sense of hurting or even being hurt (even after Henry struck him in the mouth when he took a step further from a handjob and offered him oral sex).
He suffocated his baby brother because he believed he threatened his existence without a smidge of regret or even worry of the possible repercussions that would follow if he were caught (which his father almost did when he found a pair of tracks from Patrick's boots towards the infant's room, but shut the thought out forever out of horror).
The description of him when he was five-years-old suffocating his baby brother. "He had a hard-on while doing it. This was not uncommon."
He uses animals for his "experiment" where he tortures them ever so slowly by placing them in a rusty refrigerator to freeze and starve, including a stolen cocker spaniel puppy whose torture lasted the longest.
Said boy's fate, in chapter 17. He was a sociopath with only one fear: leeches. It takes the form of leeches combined with mosquitoes and wasps. The description of the boy being drained of his blood as well as the fact that one of the leeches sucks his eyeball dry is pretty horrifying as well. Even after ripping off and squashing a bloated leech feeding off his arm, the severed head was still embedded and continued to suck out the blood even as it was spilling out the other side like a hose. He was still alive while Pennywise was dragging his bloodied body into the sewer. He woke while he was feeding on him.
What happened to Michael "Mike" Hanlon when he was a baby. While his mother was cleaning and hanging laundry outside, Mike was sitting and playing in his baby carrier when a large crow showed up and started pecking his face. It wasn't until his mother heard his cries of terror and pain that she rescued and tried to kill the crow, but it already flew away. The fact that Mike was only a baby and couldn't defend himself is the scariest thing that could ever happen in his childhood. The crow appears later as a giant, horrible monster by one of Pennywise's manifestations.
Pennywise appearing as the main character's little brother the day he died with his arm ripped off. Fortunately, the main character regains his senses and kicks Eldritch Abomination ass.
For that matter, the scene where George got his arm ripped out. Especially:
The clown seized his arm.
And George saw the clown's face change.
What he saw then was terrible enough to make his worst imaginings of the thing in the cellar seem like sweet dreams; what he saw destroyed his sanity in one clawing stroke.
What happened to Tom Rogan when he gazed into Pennywise's "deadlights". Since he was an abusive dick, he deserved having his head explode from madness.
The Deus Sex Machina. It's just so disturbing and horrible (despite being well-written, of course) that any inkling of Fetish Fuel is drained away into the bowels of Pennywise's sewer, never to be seen again. As the children fleeing the sewers, from defeating IT the first time, stop for a moment to make an entire connection via their reproductive organs.
Replacing the bonds of friendship with the bonds of love was really more of a heart warming moment than Nightmare Fuel for this troper (even if they were still kids at the time). What was Nightmare Fuel was the thought that because of the way sex is viewed in this culture, Beverly couldn't even bring her mind to acknowledge the act instead hiding beneath the gackles. Being unable to even think of the love they had for each other is terrifying.
Instead of appearing in the school shower to frighten Eddie like in the miniseries, It harasses him in the form of a homeless man offering oral sex. King's description of the homeless man and his proposition is incredibly nauseating nevertheless. The form that the monster takes afterwards based on the fear of the homeless man; the homeless man had an advanced case of untreated syphilis that Eddie (very understandably) mistakes for leprosy, so the form It takes looks pretty nauseating.
The boys being chased by It at the Neibolt Street house porch.
"Sometimes I worry about you Beverly. Sometimes I worry a lot." It's up in the air whether it's creepier coming from her own father or from It disguised as her father.
The underlying message the novel carried throughout its entirety is rather like a punch to the gut. The idea that such great chunks of our lives end up being forgotten, lost during the transition to and through adulthood.
Beverly's encounter with Mrs. Kersh. Especially when Beverly finds her cup filled with liquid shit.
Topped by Kersh turning into Beverly's father, telling her that he wants to eat her (in the sexual sense).
Adrian Mellon's death. Beaten to a pulp, dropped off a bridge and when his lover goes to look to see if he's okay, he sees Pennywise biting into the man's body, before turning his head to look at the guy.
Imagine growing up in one of the towns that King amalgamated into Derry. The murder on the bridge was based on real events in Lewiston, Maine. Near as anyone can tell, the water tower nearest there was in Norway, Maine. That book was all sorts of creepy for people native to Maine.
The fact that, when they went back as adults, IT was pregnant. And they don't know if they got all the eggs! Oh, and the Ritual of Chud, where Bill had to bite It's tongue, which is described as all gross and cracked and scabbed.
"And although the wall itself towered hundreds of feet above them, the door was very small. It was no more than three feet high, a door of the sort you might see in a fairytale book, made of stout oaken boards bound with iron strips in an X-pattern. It was, they realized at once, a door made only for children. Ghostly, in his mind, Ben heard the librarian reading to the little ones: Who is that trip-trapping upon my bridge? The children lean forward, all the old fascination glistening in their eyes: will the monster be bested...or will it feed? There was a mark on the door, and heaped at its foot was a pile of bones. Small bones. The bones of God alone knew how many children. They had come to the place of It."
"Bill toed the bones, and suddenly scattered them in a powdery, rattling drift with one foot. He was scared, too...but there was George to consider. Were those small and fragile bones among them? Yes, of course they were. They were here for the owners of those bones, George and all the others—those who had been brought here, those who might be brought here, those who had been left in other places simply to rot."
The horror and destruction It wrought whenever it awoke from its decades long hibernation. The beginning of its reign of terror in Derry, Maine in the 18th century starts with only two words - "It awoke." And of course it became worse from there, especially the incident in 1906 when 88 children were gruesomely killed during an Easter Egg Hunt caused by an explosion from Kitchener Ironworks right before It went into hibernation again.
The unfortunate destruction of the African-American military night club which was set fire by a group called the Legion of White Decency, in effect the KKK. One of the survivors, Dick Halloran, would become the cook for the Overlook Hotel. Mike Hanlon's father, Will Hanlon tells his son that on the night the club burned down in 1930 he witnessed giant bird carry off a LWD member in its talons—the same bird that nearly killed Mike in 1958 when he was an infant! Not to mention the "half-assed enema" Mr. Hanlon received from a lady's high-heeled shoe, when he was nearly trampled during the escape.
Imagine that the man you've married abuses you to the point that you mentally and emotionally regress to a child when you're around him. Welcome to Bev's life being married to Tom Regan until she has the guts to stand up to him and gives him a taste of his own medicine.
The realization that the kids had that the entire town was in a sense, in league with It, especially when they realize that even their own parents weren't going to stop It from taking them. It's bad enough as a kid to have to fight the boogeyman, but far worse to come to the conclusion that your parents are on his side and don't even know it.
The creeping horror that is the Derry town populace: no matter what sick, depraved thing happens in front of them, no matter how many people are brutally murdered in broad daylight, the people of Derry will calmly go about their business... until someone steps up to become that cycle's scapegoat. That's when they break out the pitchforks and torches, and then it's back to business the next day, not even worth mentioning the bloodbaths in the news.
Henry Bowers carved the first letter of his name into Ben Hanscomb's belly with a knife, and would have put his whole name down there if Ben hadn't fought back and gotten away. The scar faded away after Ben left Derry, and then reappeared as It began to reawaken.
The fact that Beverly's father was implied to be sexually attracted to her and abused her because of it.
Stanley Uris, one of the protagonists, commits suicide in his bathtub because he doesn't want to go back to Derry to face It again. When his wife finds him, she finds that he's written the single word "IT" on the bathroom wall in his own blood.
Pretty much all of these examples and others become even more frightening upon listening to Steven Weber's reading of the novel. His matter-of-fact narration of horrific scenes leaves the listener no quarter, and the different voices he affects for Pennywise's different manifestations are particularly chilling.
It has the ability to mimic any of Its victims, but it's never explained whether it's only mimicry, or if It really does take their souls and just uses them to lure or frighten victims. That might really have been Beverly's father... or what was left of him. And OHMIGAWD, what happens when they go on living after being possessed by IT?
The entirety of Henry Bowers' life. Between his insane father showing him approval only when committing horrible, violently abusive acts against others, and his proximity in age to It's most potent adversaries, he was just about doomed from birth.
Bill's stutter coming back. Losing your words is the ultimate nightmare fuel for any writer.
Beverly being threatened and chased by her father, and realizing "this is how it happens". Up until then it's possible to wonder why IT finds it so easy to victimize children, and why the Losers don't tell any of the other kids. IT can get you where you live... and it can consume the people you count on to protect you most.