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.
The short answer is: yes. At the end of the 1986 novel, the Losers descend back into Derry's sewers and, facing off against It in the form of a giant female spider, challenge it to the Ritual of Chüd (more on that in a second) and ultimately crush Its heart, destroying the creature once and for all.
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.
Weakened, IT runs away to tend its wounds and is chased by Bill, Richie, and Ben, who stays behind to destroy the eggs laid by IT. Bill then fights his way inside IT's body to get to its heart, crushing it and finally killing the creature.
His Survival On Earth. So something that really sticks out about Pennywise as a character is that he has been on earth for millions, if not billions, of years, but he's a character who feeds entirely on humans and their sense of fear.
Young kids fear "pretend" things.
They fear what might be under their bed or in the closet. Many are afraid of the dark and at bedtime. Some are afraid of scary dreams. Young kids may also be afraid of loud noises, like thunder or fireworks.
Pennywise's Kills Add Up Over Time
The number is then multiplied by the number of times Pennywise has awakened -- once every 27 years throughout the 270-year history of Derry, equaling ten times -- to come up with a final tally of between 12,000 and 18,000 dead.
You've also probably read all of King's horror novels, including The Dark Tower series, which reveals that Pennywise's archenemy is The Turtle.
Finally, Pennywise is beaten into submission. He scurries away, utters the word "fear," and partially disintegrates before falling into the void.
According to It, when humans got scared, "all the chemicals of fear flooded the body and salted the meat". This is why he prefers to feast on children -- their fears are simple, pure, and powerful compared to the complex, pathological fears of adults.
Every 27 years, a shape-shifting entity known as IT crawls out of the sewers to prey on the children of Derry, Maine. IT plasters himself with an unnatural grin, takes on the form of Pennywise the Dancing Clown, and wreaks havoc.
The spider-clown shrinks as the Losers hurl taunts at It, until it's tiny and weak enough that they pluck out its heart and squash it into nothingness. In the end, they defeat Pennywise by, uh, making him feel really bad about himself.
It has a low pain tolerance
Not many people can say that they have harmed Pennywise before. However, those that have may notice something very interesting about the dancing clown. It certainly does not have a very high pain tolerance for a frightening demon.
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.
In each adaptation, Pennywise attacks his victims by manifesting the thing they fear the most. For the boys in the Losers Club, that fear includes werewolves, mummies, lepers, evil paintings, and even giant birds.
With Derry, Maine as the main setting, IT follows the Losers as they come across an evil entity living in the sewers which wakes up every 27 years to feed, and to make it worse, the creature feeds off the fear of its victims and it can take any shape it desires.
In the novel, It claims that its true name is Robert "Bob" Gray, but decided to be named “It”. Throughout the book, It is generally referred to as male due to usually appearing as Pennywise.
It Chapter Two - Wikipedia
depicted the satisfying death of Pennywise while subtly hearkening back to Pennywise's first 1988 victim, Bill's brother Georgie.
The simplest and most obvious interpretation is that all the talk of floating is a reference to the fact that Pennywise (aka the titular "It") murders his victims and drags them down to the town's sewer system where he dwells, which is full of water.
It was able to create a pocket hurricane that destroyed a town, cast an illusion of itself in the moon, and was able to teleport itself to the other side of the United States. That's about the upper limit of It's power.