Invisibility: It can appear (usually as Pennywise) to only certain people and stay invisible (in both sight and sound) from others. This is seen in a few instances, like when adult Beverly encounters Pennywise at her former home or when adult Ben Hanscom encounters It in the public library.
Throughout the summer and their trials against Pennywise and the school bullies, the Losers realize that none of the adults in Derry can actually see Pennywise or the horrors he is committing against the children of Derry.
And it is not totally true that adults can't see Pennywise because there are several incident in books where adult see Pennywise but adult don't find it as a threat because of the reason that Pennywise choose not to. Pennywise only attack children as they are easily manipulated and easily scared.
When you're an adult, you dismiss the things that frightened you as a kid. Pennywise realizes that children are much more vulnerable than adults in the fear aspect.
He can and will eat teens and adults, he just prefers them young.
It feasts on the flesh of humans simply because our fears are easy to manifest and they make us taste better. According to It, when humans got scared, "all the chemicals of fear flooded the body and salted the meat".
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.
IT thrives on chaos; an exact 27-year pattern is way too predictable for a being of pure evil. Rather, IT wakes up roughly every three decades, and stays away for a different period of time.
It's weaknesses are courage and heart. For the sake of spoilers, I won't go too much into the Ritual of Chüd, but suffice it to say that if you want to defeat It, you've got to have the two traits listed above.
Film: At the house on Neibolt Street, the kids basically do a bunch of damage by impaling It with rods. It looks like they get these weapons from the rusty wrought-iron fence of the house itself. Down in the sewers, during their final encounter, it's much of the same.
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.
Literature. In the novel, It is a shapeshifting monster who usually takes the form of Pennywise the Dancing Clown, originating in a void containing and surrounding the Universe—a place referred to in the novel as the "Macroverse".
The concept of clowns has been traced back to the Fifth Dynasty of Egypt, but the modern circus clown developed in the 19th century, so by the time King's novel is set (the first part of it), Pennywise was around 200 years old.
IT is terrifying. While it may seem counter-intuitive at first, we're attracted to Pennywise because he scares the hell out of us. Clowns scare so many people that the fear has an official title – Coulrophobia. In fact, more Americans are scared of clowns than they are of climate change.
Image via Warner Bros. Finally, Pennywise is beaten into submission. He scurries away, utters the word "fear," and partially disintegrates before falling into the void. It's a powerful defeat of a powerful monster, and it's satisfaction enough were IT to remain a single film.
As there's no absolute time frame when it comes to IT's hibernation, the IT miniseries chose to let it sleep for 30 years, and the film went with 27, just like the novel.
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.
Son Goku - Dragon Ball Super
Considered the most powerful warrior in the multiverse, Son Goku would handily defeat Pennywise in a tussle.
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.
Throughout the novel (and its adaptations), IT kills many, many people, mostly children as their fears are easier to represent (as explained in the novel, the fears of adults are more complex and abstract, making it more difficult for IT to take a specific shape), but it never got to the Losers (at least not when they ...
What symbolizes a child's sense of imagination is manipulated to lure children to the clown, Pennywise (Bill Skarsgård). Pennywise's most notable ability is to manifest as each of the children's fears. Whenever the red balloon appears, it signals that Pennywise is close, if not already present.
This proves to be its undoing; Eddie nearly chokes it when it takes the form of a leper and is small enough for him to do that. When sufficiently weakened, the Losers kill It by crushing the heart it must have in the form of Pennywise the Dancing Clown.
A god of destruction, not just of our world, but of multiple worlds and even multiple universes. It originated in a vast cosmic void between worlds that has been called, at times, the Macroverse, and in King's Dark Tower series, the Todash Darkness, in a space It refers to only as the Deadlights.