The Joker earned his reputation due to the absurd and ridiculous crimes he commits every time he appears. His crimes can vary from a simple prank to the near genocide of the entire planet. This has made the Joker one of the most dangerous criminals around, as no one knows what his next major crime will be.

Most criminals have a goal that they're working towards. Criminals who are motivated by money, for example, tend to rob banks or go for something more "highbrow," like embezzlement. While that's terrifying for the people in the bank, the criminals don't tend to escalate past that. That's not the case for characters like the Joker, though. The Joker has a bizarre variety of crimes that he's more than happy to commit, and it seems that he's only been escalating more and more over the past decades, as he's done some truly terrible things.

10 The Joker Nearly Poisoned All of Gotham City

Batman: The Man Who Laughs #1 by Ed Brubaker, Doug Mahnke, Patrick Zircher, and Aaron Sowd

Because of how many times DC has rebooted its history, it's hard to narrow down exactly the first chronological appearance of a character in continuity. Despite the Joker's origin being shrouded in mystery, his first encounter with Batman is pretty easy to find. DC typically treats Batman: The Man Who Laughs as the official first time that Batman and the Joker have encountered one another. This comic is referenced constantly throughout Batman's history, including in Batman: Death of the Family and Batman: Hush 2.

This story features the Joker's first appearance in Gotham, where he was completely uninterested in Batman himself. Instead, the Joker was fixated on taking revenge on Gotham City for reasons that are never made clear. The Joker intended to do this by poisoning the Gotham City water supply, but, thankfully, Batman stopped him before he could.

9 The Joker Once Cut Off a Man's Skin

Joker by Brian Azzarello and Lee Bermejo

Despite being dressed like a clown, the Joker is a brutal criminal, and no one should cross him. A former associate known as Monty learned this the hard way, when, after the Joker was sent back to Arkham Asylum, Monty began making moves in the criminal world that the Joker didn't appreciate. When the Joker was released from Arkham, he wanted to settle some debts with people, and one of them was Monty.

Poor Monty was pulled into the back of a club for a one-on-one meeting with the Joker, and it really didn't go in his favor. After only being alone with the Joker for a bit, Monty came stumbling back out into the club, completely skinned. All the skin below his head had been removed by the Joker. It's no surprise that Monty didn't live very long after this, and there's no doubt that his final moments were completely excruciating.

8 The Joker Paralyzed Barbara Gordon for Life

The Killing Joke by Alan Moore and Brian Bolland

One of the most brutal and famous crimes that the Joker ever committed was when he shot Barbara Gordon, severing her spine in the process. This moment forever changed the direction of both the Joker and Barbara Gordon's characters. Though Moore's intentions for the "canonicity" of The Killing Joke are up for debate, it's true that Barbara Gordon had recently retired from being Batgirl, making her injury at the hands of the Joker all the more tragic. For his part, the Joker's shooting of Batgirl boosted him into incredible popularity, cementing him as Batman's greatest villain.

But just shooting Babs is clearly not sadistic enough for the Clown Prince of Crime. After shooting her, he then stripped her naked and photographed her naked body, all so he could try and use this to drive her father insane. It is perhaps one of the darkest things that the Joker has ever done and certainly one of his worst crimes.

7 The Joker Beat Robin Jason Todd and Blew Him Up

Batman #427 by Jim Starlin and Jim Aparo

The same year that the Joker shot Barbara Gordon in The Killing Joke, DC decided that the Clown Prince should be the one to kill off the unpopular Robin, Jason Todd. This decision resulted in a frankly convoluted storyline where Jason Todd set off to Qurac to find his missing mother, and the Joker ended up as the ambassador of Iran. It was an absurd story, but it left an undeniable mark on Batman's history.

After Jason finally found his mother, he was horrified to learn that she was working for the Joker. His mother turned Jason in to the Joker, and Jason was savagely beaten with a crowbar before being left with a bomb, which eventually exploded and killed him. Shooting Barbara Gordon was certainly a dark moment in Batman's mythology, but killing a Robin had never been done before. But of course, the Joker didn't stop at just child murder.

6 The Joker Shot Sarah Essen-Gordon in a Room Full of Babies

Detective Comics #741 by Devin Grayson, Greg Rucka, Dale Eaglesham, and Damion Scot

During the events of No Man's Land, a major '90s Batman crossover, Gotham was in complete chaos. Criminals were running rampant, and both Batman and the GD were struggling to maintain control. Things only got worse when the Joker appeared and decided to add to the chaos. After the Joker kidnapped dozens of babies, it was up to Sarah Essen-Gordon to try and save them, as she was the first to track the Joker down. Unfortunately, she proved to be no match for the Clown Prince of Crime.

While murdering a child is certainly awful, killing a woman in a room full of infants is just a bit more horrific.

During their confrontation, the Joker tossed one of the babies at Sarah. In a moment of pure reflex, she immediately dropped her gun in favor of catching the infant, which was all the opening that the Joker needed. With Sarah now helpless, the Joker simply walked up and put his gun against her head, killing her. While murdering a child is certainly awful, killing a woman in a room full of infants is just a bit more horrific.

5 The Joker Blew Up an Entire School Full of Children

Batman: Cacophony by Kevin Smith and Walt Flanagan

It's safe to say that the Joker shouldn't be allowed around children. He killed Jason Todd, shot Sarah-Essen in a room full of infants, and once blew up an entire school full of children just to spite a criminal rival. When Maxie Zeus began creating a drug using Joker Venom, the Joker, naturally, took offense. To prove that he wasn't someone to be messed with, the Joker found where Maxie's nephew went to school and then blew it up.

This attack sent a very clear message that there is no line that the Joker will not cross to get what he wants, which has pretty much always been true about the character. The Joker is unpredictable and will go to any length to achieve his goals. He has beaten children with crowbars, shot women in front of babies, and poisoned dozens of kids. With all of that in mind, blowing up a school full of kids hardly seems like something that would phase him.

4 The Joker Turned the Justice League into Supervillains

Batman: Endgame by Scott Snyder and Greg Capullo

The Justice League are the greatest heroes on Earth, which is why it was so twisted that the Joker transformed them into supervillains. The Joker's infamous Joker Venom transformed Aquaman, Wonder Woman, the Flash, and Superman into monsters who only had the goal of murdering Batman. Batman is forced to fight off the Justice League in a brutal battle in the streets of Gotham.

While Batman succeeded in subduing his friends, it's still pretty scary that the Joker was able to poison the Justice League and turn them into monsters. If the Joker had set them loose on the world, instead of focusing on Batman, the death toll would likely have been in the millions. As far as crime goes, poisoning the Earth's greatest defenders is hard to beat.

3 The Joker Turned All of Gotham into Maniacs

Batman: Endgame by Scott Snyder and Greg Capullo

The Joker loves nothing more than proving that everyone can be just like him if they're given just the right push. To prove this point, the Joker unleashed his most vicious version of his Joker Venom yet when he transformed nearly everyone in Gotham into homicidal maniacs. This venom twisted people's feelings, turning affection into hate, meaning people would seek out their loved ones to attack first. This venom very nearly caused Gotham to tear itself apart.

Because of the Joker, Gotham City was essentially turned into something out of a zombie apocalypse movie. The streets were filled with roaming maniacs looking for the next person to attack. While Batman eventually cured Gotham, this story was still a chilling look at a city where the Joker's philosophy reigns supreme and everyone gives into their worst instincts.

2 The Joker Literally Ate All of China

Emperor Joker #1 by Joe Kelly, Jeph Loeb, Duncan Rouleau, Todd Nauck, Carlo Barberi, Scott McDaniel, Marlo Alquiza, Jaime Mendoza, Richard Bonk, Tanya Horie, and Richard Starkings

It's well-known that the Joker has absolutely no issues with murder. He loves it, even. But he took things a bit too far when he murdered the billion people living in China. Using god-like power, he simply ate every single person living there as if they were Chinese food. Even with god-like power, the Joker never lost his sadistic sense of humor. It also goes to show that the Joker's homicidal impulses have only ever been reigned in by what he was practically able to do.

As horrifying as it is that the Joker has killed dozens of children and infected thousands of people, what's even more horrifying is that he would do more if he had the power to do so. Given the power of reality warping, the Joker immediately takes his crimes to a genocidal level, going from killing hundreds of people to billions.

1 The Joker's Worst Crime Is Undoubtedly Omnicide

Emperor Joker #1 by Joe Kelly, Jeph Loeb, Duncan Rouleau, Todd Nauck, Carlo Barberi, Scott McDaniel, Marlo Alquiza, Jaime Mendoza, Richard Bonk, Tanya Horie, and Richard Starkings

It's hard to count just how many people that the Joker has killed, especially since, at one point, he had killed practically everyone in the entire DC Universe. When the Joker possessed Mr. Mxyzptlk's reality-warping powers, he used them to erase everyone in existence. While Superman and Batman were spared, pretty much everyone else was gone, which means that the Joker's murder count is in the trillions, if not higher. There really isn't any greater crime in the Joker's history.

The Joker has killed thousands of people. He's murdered men, women, and children. He has poisoned people. He has turned friends into enemies. He's caused the genocide of entire countries. But there's simply no crime that reaches the level of erasing all life in the entire universe. Only the Joker could come up with such an absurd crime.