There are a lot of characters who can do kill him who are universal or higher, like Thanos w/ IG, Giratina, Dimentio, and Arceus, to name a few of the literal hundreds. Spawn is the first thing that comes to my mind.
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.
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.
As a team, the Avengers would absolutely annihilate Pennywise. It's not even a fair fight. If a group of children can overcome It, Earth's Mightiest Heroes shouldn't have too much trouble. Pennywise simply doesn't have the means to hurt the likes of Thor and The Hulk.
If this were to happen, you better start running, because without a doubt, Pennywise would win in a fight against any other evil character, let alone a human. Pack it up Michael Myers. For starters, Pennywise is supernatural. His biggest strength is his ability to read and manipulate minds.
Film Theory: How To BEAT Michael Myers (Halloween)
Can Pennywise beat venom?
Pennywise. Pennywise, it would know Venom's fears and use them against him. Like Pennywise would take on a Symbiotes only natural predator in the Xenophage and eat Venom. Pennywise is probably a bit overpowered for Venom, excepting maybe the KIB version, but even then I think "It" is more versatile.
The cinematic adaptation of Stephen King's IT Chapter Two depicted the satisfying death of Pennywise while subtly hearkening back to Pennywise's first 1988 victim, Bill's brother Georgie.
I seriously doubt that Pennywise could scare The Hulk in any way or form, plus Hulk is an adult, so I am going to say Hulk easily sends Pennywise back to sleep for another 27 years. Hulk: “SMASH!”
Ghost Rider. He would have no fear of Penny wise and has the tools to destroy him. Pennywise thrives on fear and would have no weapon against Ghost Rider.
With the stones, Thanos could take out Pennywise easily, using the soul and reality stones to show where the real monster is, and then kill him with the power stone. But without them, it would take much longer. But in the end, Thanos would still win.
If you want to get technical, It is an alien, but It's origin goes well beyond that. It is actually an ancient cosmic deity. A god of destruction, not just of our world, but of multiple worlds and even multiple universes.
The Atlantic said of the character; "the scariest thing about Pennywise, though, is how he preys on children's deepest fears, manifesting the monsters they're most petrified by (something J. K. Rowling would later emulate with boggarts)." British scholar Mikita Brottman has also said of the miniseries version of ...
Pennywise can possess people, cause hallucinations, control minds, warp reality to his ends, can invade the dreams of his victims, make himself invisible at will, and read minds. Thus, Pennywise is pretty definitively stronger and more powerful than Art the Clown.
As long as Pennywise instills fear in his victims, he grows in size and has godlike powers. When the losers learn not to fear him, he shrinks to the size of a helpless toon, and is easily defeated. Batman is known for being rational, and having a firm grip on his mental state. Pennywise doesn't stand a chance.
The novel explains that IT landed on Earth during an asteroid impact and established itself under the land Derry would be later built on, and initially preyed on indigenous tribes. From that point of view, IT/Pennywise would be billions of years old, but his clown shape wouldn't be that old.
Now, when the Losers crushed IT's heart while in its spider form, they killed IT's physical form and severed its connection to Derry, thus why the town was destroyed, but the true entity still lives in another plane of existence.
As powerful as Cosmic Ghost Rider is, Immortal Hulk would destroy him. Castle couldn't do anything that would actually kill him, which would give Immortal Hulk time to destroy his foe.
Like his namesake suggests, Saitama aka One-Punch Man would take Pennywise out with a single death blow. As the single most powerful anime character of all time, he would ensure Pennywise never made it out of the first round.
Despite his immense power, the Hulk has been defeated by heroes like Wolverine, Iron Man, Puck, and the Punisher. Spider-Man, Fantastic Four, and the Thing have also managed to take down the Hulk using their intelligence, teamwork, and unique abilities.
Conclusion: Captain America could take out Movie Version of Pennywise but not the True Form that can transcend the narratives and destroy timelines and universe with ease.
But, the film makes clear, It (sometimes written as “IT”) isn't just a clown. Oh no. As detailed in King's novel, he's an ancient, cosmic being, described in the novel as an “Eater of Worlds”, who is able to adopt a variety of nasty guises.
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.
Throughout Stephen King's It, Pennywise is referred to as a male, but author Stephen King pulled a fast one on readers in the It book ending by revealing the creature's true form was a pregnant spider, implying that it is, in fact, biologically female.
