When the Joker debuted in 1940, he was more of a serial killer than anything else. He just also happened to use ingenious methods of killing his victims. It wasn't until National Comics (later DC Comics) decided to tone down the violence in their comics that Joker began to really embrace the idea of playing "pranks" as part of his crimes. Years later, when relaxed standards regarding violence allowed for the Joker to return to his murderous ways, the pranks remained as part of his characterization.

RELATED: The 15 Worst Things Batman Has Ever Done

Therefore, this list (which we not-so-coincidentally decided to release on April Fool's Day) will count down the deadliest pranks that the Joker has pulled off over the years in the comics. Not every Joker story really revolves around a gag (killing Jason Todd was just a happy coincidence for him), but of the ones that do, these are the most twisted and deadly of them.

15 PROVIDING HOPE

The "Batman" titles in late 1998 were in a weird place. The whole line was about to be turned upside down with "No Man's Land," where there would no longer be regular writers on any of the main "Batman" books. However, the outgoing writers still had a few months on their respective titles (which had all been involved in a crossover where Gotham City was rocked by a massive earthquake) before being replaced. So the writers had to try to tell post-Earthquake stories while not messing with the incoming status quo.

In "Detective Comics" #726, Chuck Dixon and Brian Stellfreeze answered the call with a brilliant one-off issue where the Joker manipulates a criminal who had been in the cell next to him into kidnapping a little girl. The Joker tells Batman where she is with just seconds before she runs out of air. When Batman returns to ask why, the Joker reveals that he knows that Batman is pragmatic enough to presume that in situations like these, the victim is already dead. With this last-second rescue, though, Batman will always have hope in the future, and that will just torture him even more when they are dead.

14 TRYING TO MAKE BATMAN HAVE THE LAST LAUGH

The Joker was famously revamped for the modern era by Denny O'Neil, Neal Adams and Dick Giordano in "Batman" #251. However, while that issue brought back the Joker's killing ways, it was about the Joker getting revenge on some former henchmen that he felt had screwed him over, so the issue was mostly straightforward killing and light on gags.

The next appearance of the Joker, though, in "Batman" #260 (by O'Neil, Irv Novick and Giordano) was all about the Joker dousing Batman with a special version of Joker's laughing venom where Batman would laugh uncontrollably every time he heard a joke until he eventually would die from laughing himself to death! The only poison expert who could cure him was captured by the Joker in London and almost killed. Batman, though, luckily realized that the poison only made him laugh at bad jokes, so he just concentrated on all his favorite Marx Brothers movies and was able to defeat the Joker and get a cure.

13 LEAVING SOMETHING TO REMEMBER HIM BY

In "Batman" #353 (by Gerry Conway, Jose Luis Garcia-Lopez and Dan Adkins), the Joker is shocked to learn that Gotham City is tearing down part of a famous transportation station and building a new statue in honor of a famous Broadway performer. How dare Gotham City honor an entertainer other than the Joker?! So he steals a computer that can use explosives as well as a surgeon can use a scalpel and the Joker plans to blow up a mountain side at the top of Gotham so that his face is sculpted into the mountainside by the explosives.

The extra twist? Guess who is tied up to the mountainside along with all of the explosives? Yes, you guessed it, it's Batman! Talk about killing two birds with one stone (or should it be two bats with one stone?). Of course, Batman being Batman, he found a way out of his deadly trap. This was the last issue of "Batman" drawn by the great Jose Luis Garcia-Lopez for nearly 20 years (he did a "Batman" graphic novel 16 years later), so it really stood out from an art standpoint.

12 OEDIPUS WRECKING DAMIAN WAYNE

In "Death of the Family," the Joker decided that he was sick of how Batman had changed their initial relationship by expanding the game from just Batman and Joker to suddenly an entire family of Bat-themed vigilantes. So when Joker made his triumphant return to the "Batman" comics for the first time since he disappeared after his face was cut off by the Dollmaker, he targeted Batman's fellow vigilantes, including the current Robin, Damian Wayne.

In "Batman and Robin" #15-16 (by Peter Tomasi, Patrick Gleason, Mick Gray and Keith Champagne), the Joker forced Robin to fight a battle to the death against his own father, who was brainwashed by the Joker's venom. In the end, Damian refuses to kill his father, allowing himself to be killed instead. The Joker then sets off an explosive hidden inside of Batman. The shocked Damian then realizes that it wasn't the real Batman after all, as the Joker pulled off a twisted joke on the Boy Wonder.

11 TRYING TO MAKE BATMAN DISAPPEAR

In "Detective Comics" #833 (by Paul Dini, Don Kramer and Wayne Faucher), Batman had an uneasy reunion with his old friend, Zatanna, who Batman had recently discovered had used magic to erase some of Batman's memories after he discovered that she and some other members of the Justice League were messing with the brains of captured supervillains to try to reform the villains. They were teaming up because it appeared as though a magician acquaintance of Zatanna's might have murdered his assistant.

When Batman and Zatanna investigated the magician, he took them by surprise by shooting Zatanna in the neck (she typically needs to say her spells out loud for them to work), tossing her into a flooding chamber and then knocking Batman into an electrical chair. The magician then revealed that he was secretly the Joker in disguise! Luckily for Zatanna, writing your spells out in your own blood also worked, so she was able to heal her wounds by the time Batman freed her from the flooded chamber.

10 LAUGHTER AFTER MIDNIGHT

In a story in the first "Batman Adventures Annual," Paul Dini and artists John Byrne and Rick Burchett (doing a stunning representation of the famed Bruce Timm-style of artwork) show what happens to the Joker when he is out in Gotham late at night. He ends up terrorizing everyone he encounters along the way, including throwing a grenade at an angry Gotham resident who got mad at the Joker for making too much noise on the streets late at night. The centerpiece of the pranks, though, centered on a donut shop that is open all night.

The prank involved the Joker paying for some donuts with a special bill with the Joker's face on it. When the nervous cashier questions the Joker, the Joker reveals that the sweat from the nervous cashier has now activated the poison hidden on the bill. The end result was the cashier being killed by the Joker venom. The cruel randomness of the murder was shocking (and wow, that art by Byrne and Burchett! So good!).

9 USING THE ENTIRE SUPERVILLAIN COMMUNITY FOR A FINAL JOKE

In the crossover event, "The Last Laugh," the Joker discovered that he had an inoperable brain tumor and that he was near death. With his mortality in full view of himself, he decided to pull off one massive final joke. His idea was to pull off a major prison break from the supervillain prison where he was being incarcerated. He planned to do this by killing one of his fellow prisoners, Multi-Man, repeatedly, because the Multi-Man's power is that every time he died, he would come back to life with a new superpower. The Joker killed him until he gained a power that would help them escape.

Once they were freed, though, the Joker exposed them all to his Joker Venom, so now the whole supervillain community was "Joker-ized." He set them upon the world's superheroes in the hopes that one of them would then kill him now so that he could die laughing. In the end, though, the real prank was by the doctor who had lied to him about the tumor, simply because he wanted to make the Joker suffer.

8 HANDING OUT SOME DEADLY TREATS

In Frank Miller and Klaus Janson's "The Dark Knight Returns," Batman has returned to the rooftops of Gotham City after a 10-year hiatus. During that hiatus, a psychologist has been touting his ability to cure the supervillains of Gotham, including the Joker. It is his contention (and a contention that Miller does not automatically dismiss) that Batman sort of drew the insane criminals to Gotham City like a clarion call. In any event, the newly "cured" Joker is booked on a late night talk show along with the man who cured him.

The Joker then promptly murders everyone in the studio with some of his Joker venom in gas form. He then escapes to a local carnival where a contingent of boy scouts are attending. The Joker gives out free cotton candy to the scouts, killing over a dozen scouts with the poisoned treats. He then attempts to blow up a roller coaster filled with scouts, but Batman and Robin arrive to stop him.

7 JOKER PUTTING A NEW SPIN ON A PAIR OF CLASSIC GAGS

Both of these pranks were relatively minor in the grand scheme of things, so we've decided to combine them into one single entry. As we noted earlier, when the Joker made his triumphantly murderous return in "Batman" #251 (by Denny O'Neil, Neal Adams and Dick Giordano), he mostly just murdered his old henchmen through normal methods (typically just Joker venom) but one of them he kills with an exploding cigar, a cigar that just happened to be filled with nitroglycerin!

Similarly, in "Batman" #321 (by Len Wein, Walter Simonson and Dick Giordano), the Joker decides to celebrate his birthday by kidnapping the most prominent citizens of Gotham City and then exploding them with giant candle-shaped rockets atop a giant birthday cake! When he jokes about how this will be the best birthday present since the catcher's mitt he got as a kid, one of his henchmen did not laugh. That was a big mistake. The Joker then shoots at him with a prop gun..and then the prop shoots into the henchmen's eyeball.

The real message seems to be never to work for the Joker if you're a henchman.

6 SERVING A TWISTED DINNER

As noted before, "Death of the Family" is all about the Joker deciding that he doesn't like how the so-called "Bat-Family" has ruined the special dynamic that he and Batman had going on. He then went around capturing each member of the group (thus turning the event into a multi-title crossover, each with a special Joker die-cut cover featuring their faces covered by the Joker's face) and seemingly discovered each of their secret identities. He tied them up and they were all covered with bloody facial bandages and could not feel their faces due to having been anaesthetized.

The Joker had previously had his face removed by the villainous Dollmaker, so in a twisted sequence, he seemingly removed the faces of the Bat-Family and served them their own faces for dinner! Luckily, not only did the Joker not actually remove their faces, but also he did not even discover their secret identities. As it turned out, he just didn't care about them at all. He only had eyes for Batman.

5 TOYING WITH SUPERMAN'S EMOTIONS

In "Action Comics" #719 (by David Michelinie, Kieron Dwyer and Denis Rodier), Lois Lane is poisoned by the Joker through a toy he had sent Superman as a taunt. As it turned out, the toy was covered with a deadly toxin that was going to kill Lois Lane in a matter of hours.

Superman tracked the Joker down (with Batman's help) and the Joker revealed that the only antidote was to inject a separate toxin into the Joker's blood, killing him. The toxin mixed with his blood would then serve as an antidote for Lois' poison. Thus, to save Lois, Superman would have to murder the Joker. Superman ultimately couldn't do it, and had to watch Lois die...and then come right back, just as the Joker knew would happen. He just wanted Superman to kill him for no reason. Lois, though, was not thrilled that Superman was willing to let her die.

In the "Injustice" video game, Superman's turn to villainy happened after the Joker tricked him into killing Lois Lane. That's not really a comic book (although it was adapted into a comic), so we're not counting that for the list.

4 SLAYRIDE

In "Detective Comics" #826 (by Paul Dini, Don Kramer and Wayne Faucher), Robin was in the middle of a fight against some bad guys when he was forced to retreat. When a car pulled up to him and opened its door, Robin took the opportunity to escape to seeming safety. Of course, as it turned out, the car had been stolen by the Joker.

The Joker then came up with the idea of taking Robin on a Christmas "slayride," driving around Gotham City with Robin tied up next to him, being forced to watch the Joker use his car to kill innocent bystanders. As seen in the picture above, the Joker even takes the time to phone in a hit and run! Later, the Joker visits a fast food restaurant and kills the manager when his order is screwed up. Luckily, Robin plays to the Joker's love of the Marx Brothers and distracts him long enough to be able to attack the Joker and stops his murderous rampage.

3 THE LAUGHING FISH

During his acclaimed, albeit brief, run on "Detective Comics," writer Steve Englehart used most of Batman's most notable rogues. Artists Marshall Rogers and Terry Austin got to give their own particular spin on the design of the villains, including the Joker, who was only a few years into his O'Neil/Adams revamp. In "Detective Comics" #475-476, the Joker pulled off one of his strangest pranks by infecting all of the fish within Gotham Harbor with a form of Joker venom.

He then insisted that he should get paid a royalty for each fish sold as a "copyright." When he was informed that this was crazy, he decided to try to kill the heads of the Copyright Office until they changed their minds. Therefore, Batman had to protect the members from the Joker's rampage (in an homage, of sorts, to his first story, where the Joker vowed to kill a number of prominent citizens who were all under strict guards). One of the victims is killed by a poisoned cat with Joker's grin on its face!

2 GETTING THE LAST LAUGH

As we mentioned earlier, one of the theories given at least some lip service during "Batman: The Dark Knight Returns" is the idea that Batman's presence in Gotham City serves as a beacon to the crazed killers out there like the Joker and that if Batman left, so would they. The Joker was absent for the entirety of Batman's decade-long retirement. Whether that is true or not, Batman was dealing with that public perception as well as the general cold shoulder from the police department to his return.

Things got worse when he took down the Joker after the Joker returned to murdering, as well. They had a final battle in a funhouse and Batman succeeded in defeating the Joker, but used a little too much force. The Joker was crippled, but alive. Knowing, though, that if Batman was a murderer, he would never be left alone, the Joker twisted his own spine until he died, so that it would look like Batman murdered him. Talk about getting the last laugh!

1 TESTING A TWISTED THEORY

Alan Moore and Brian Bolland's graphic novel, "Batman: The Killing Joke," is by far the most famous Joker story ever and, at the same time, it is also his most twisted prank. The notion behind the story is that the Joker is still haunted by the night where he became the Joker (Moore and Bolland tell a possible origin story for the Joker in the issue, where he is tricked into becoming the Red Hood and then ends up transformed into the Joker) and wants to see if he can make someone else snap as well by giving them "one bad day."

Therefore, he surprises Commissioner James Gordon on his birthday by breaking into Gordon's home, shooting (and paralyzing) Gordon's daughter, Barbara (who Joker did not know was also the superhero known as Batgirl), and then psychologically tortured Gordon (along with photos of Gordon's wounded daughter). In the end, though, Gordon does not break and, when Batman shows up to rescue him, he insists that Batman take the Joker down "by the book."

What's the craziest prank that you've seen the Joker pull over the years? Let us know in the comments section!