Starting in the late 1950s, DC Comics began doing so-called "Imaginary Stories." These were out-of-continuity tales featuring major characters where anything could happen and it wouldn't affect the main title. Superman and Lois Lane could get married, Batman could retire, etc. Once you give writers this much freedom, don't be surprised by how soon they start killing off characters. Sure enough, soon after the "Superman" titles began doing these types of stories, there was a classic "Death of Superman" story in "Superman" #149 by Jerry Siegel, Curt Swan and George Klein.

RELATED: Wolverine: His 15 Greatest What If...? Deaths

We bring this up to put Marvel's "What If...?" comes into perspective. "What If...?" comics are famous for how every other issue somehow ended up with tons of people dying. If Spider-Man left his apartment at 10:30pm in the regular comic book story and 11:00pm in the alternate version, in "What If...?", that change would often result in at least a dozen major characters being killed. Of course, that's just following in a long comic book tradition of using alternate realities to kill lots of characters. With that in mind, enjoy Spider-Man's greatest "What If...?" deaths.

15 WHAT IF...THE AVENGERS LOST OPERATION:GALACTIC STORM?

This is last on the list because it represents a common tradition in "What If...?" comics, where the entire world gets destroyed in a single page. However, in this instance, Spider-Man at least saw his death spotlighted as the entire world was destroyed. In "What If the Avengers had lost Operation: Galactic Storm" from "What If...?" #55 (by Len Kaminski, Craig Brasfield and Frank Turner), the Kree-Sh'iar War takes a turn for the worse (for Earth) when the Avengers stop Deathbird from killing the Kree emperors.

You would think that that would have put the Kree emperors into the debt of the Avengers, but instead it just allowed them to go through with their original plan, which was to destroy Earth! We see Spider-Man cradling the dead body of Mary Jane before the entire planet is destroyed. It's a bleak story, but at least the Avengers get a change to "avenge" their fallen planet in the second part of this rare "What If...?" two-part tale.

14 WHAT IF...THE X-MEN LOST INFERNO?

In one of the all-time great issues of "What If...?", "What If...?" (Vol. 2) #6 (by Danny Fingeroth, Ron Lim and Keith Williams), we see what happened when the X-Men failed to prevent the invasion of Earth by demons in the crossover, "Inferno." The X-Men and most of the other heroes on Earth were possessed by demons. The only remaining heroes left to fight back are a ragtag team consisting of Doctor Strange, Thor, Baron Mordo, Shadowcat, Human Torch, She-Hulk, Spider-Man and The Captain (Steve Rogers, as this came out during the period where he had given up the name "Captain America").

During their desperate assault on the headquarters of the possessed heroes, the assault team was quickly taken apart (the other side had Hulk!) and Spider-Man, in particular, was hurt by the cramped space, not giving him enough room to use his Spider-Sense to avoid attacks. Thus, he was unable to avoid being stabbed by Wolverine. Luckily, after Thor sacrificed himself to let the survivors escape, the remaining heroes managed to wipe the demons out (of course, it required sending Earth back to the Stone Age, but hey, at least they stopped the demons).

13 WHAT IF...MARVEL's SUPER-HEROES LOST ATLANTIS ATTACKS?

In "What If...?" (Vol.2) #25 (by Jim Valentino, Rik Levins and Ralph Cabrera), we see what would have happened had Set actually managed to come to Earth during the 1989 Marvel Annuals crossover "Atlantis Attacks." Set's plan involved a few different moving parts going his way, including an attempt to drug the people of Earth with a substance that would transform them into lizard people, as well as using seven powerful female superheroes as his brides. This would bear him serpent children on Earth and then he would enter the dimension himself.

Punisher and Moon Knight were able to stop the drug from spreading in the regular universe, but they failed in this comic, so most of Earth was transformed into lizard-like creatures, including Spider-Man! A small unaffected group of heroes and villains tried to stop the bad guys, including Hulk, Doctor Doom, Wolverine and Sabretooth. The Hulk killed the transformed Spider-Man. Ultimately, the Seven Brides showed up and killed all of the resistance and Set took over Earth. His children spread to other dimensions, as well.

12 WHAT IF...SPIDER-MAN MARRIED BLACK WIDOW?

In the original volume of "What If...?", the 34th issue was a special extra-sized humor edition of the comic book. Basically, it was filled with short one-panel based on humorous "What If...?" scenarios, like "What if Thor had a Swedish accent?" or "What If...Cyclops' force beams came out of his ears?" plus occasionally slightly longer strips like, "What If...Daredevil was deaf instead of blind?" Amusingly, at least one of the gag strips ("What if Silver Surfer, White Tiger, Night Rider, Iceman and Moon Knight fought Wendigo in a snow storm?") was used in an actual comic. John Byrne, for example, later did an issue of "Alpha Flight" where Snowbird fought a villain during a snowstorm that caused a whiteout, so for a few pages, all of the panels were whited out, and you could only see the dialogue.

In one of the short strips (by Mike Carlin, Ron Zalme and Brett Breeding), there is a humorous bit based on the fact that female Black Widow spiders occasionally eat their mate after mating (sometimes even during mating), although that fact has been generally over-exaggerated, it is not a standard action of the female Black Widow spider. Still, it made for this fun little joke... which is also a tad disturbing.

11 WHAT IF...?: ARACHNAMORPHOSIS

Later in the run on the second volume of "What If...?", Marvel stopped making them explicitly "What If...X hadn't happened?" and made them more just general alternate futures. In "What If...?" #88 (by Ben Raab, Ariel Oliveti and Agostin Comoto), the story is dubbed "Arachnamorphosis," and it is about Peter Parker trying to raise his son, Benjamin, who is a mutant. Peter is trying to control what he believes is Benjamin's metamorphosis into becoming a spider-monster, but he doesn't realize that his obsession (and his experiments on himself) is only turning himself into a monster!

Ben, meanwhile, is constantly bullied by Butch Thompson, son of Flash Thompson. His only friend is Sara Joy Watson. One day, after Butch beats Ben severely, Butch is found murdered. Flash and his friends seek out Ben to kill him in revenge, but Peter (who has now fully transformed into a monster) saves Ben and offers himself up instead. Peter is then beaten to death by Flash and his friends. Ben subsequently enrolls in Professor Charles Xavier's School for Gifted Youngsters.

10 WHAT IF...THE SCARLET SPIDER KILLED SPIDER-MAN?

Actually, the very last traditional "What If...?" issue came out two issues before "Arachanmorphosis," and it also was a Spider-Man death story. "What If...?" #88 (by Terry Kavanagh, Doug Braithwaite and Sean Hardy) was essentially an alternate ending to the Clone Saga. Just like in the original story, at one point Peter Parker is controlled by the Jackal (although, since Peter turned out to not be the clone, it's kind of weird that the Jackal was able to control him like that) and turned into an automaton. In the original comics, Peter was able to break free, but in this story, Ben Reilly, the Scarlet Spider, was forced to kill Peter.

In the aftermath, Ben was injured as well, and when he was found, everyone thought that he was Peter. So, he took over Peter's life, including being married to Mary Jane and taking care of her daughter, May, who had a rare blood disease. In the end, Green Goblin showed up just like he did in the regular comic, but Ben was able to defeat him and find a cure for May's disorder. Mary Jane, though, finally admits that she knows that he is really Ben. She tells him he needs to go live his own life now, although she thanks him for what he has done for her and her daughter.

9 WHAT IF...THE PUNISHER KILLED SPIDER-MAN?

Longtime Marvel fans likely know that the Punisher was introduced in "Amazing Spider-Man" #129, hired by the Jackal to kill Spider-Man. Punisher realized that Spider-Man wasn't a bad guy (like the Jackal had convinced him that he was), so he stopped trying to kill him. In "What If...?" #58 (by Chuck Dixon, Gordon Purcell and Andrew Pepoy), however, the Punisher learned the truth too late. Here, he actually found a way to kill Spider-Man (which is a clever way that you figure more villains should try, which is to rig something to explode as soon as Spider-Man enters a room, so even if his Spider-Sense warns him, it will be too late for him to get away).

Once he discovered he had been played, the Punisher found himself hunted down by all of the superheroes of New York, but also welcomed by the villains of New York, which he used to his advantage by killing a bunch of Spider-Man's foes while they threw a party for him. Ultimately, he discovered the Jackal's true identity of Doctor Miles Warren and then called the cops while holding a gun on Warren. Once surrounded by the cops, knowing that they'd mow him down as soon as he pulled the trigger, he told Jackal that he'd see him on the other side.

8 WHAT IF...KRAVEN THE HUNTER KILLED SPIDER-MAN?

At the beginning of the classic J.M. DeMatteis, Mike Zeck and John Beatty storyline, "Kraven's Last Hunt," Kraven has Spider-Man captured and has a gun trained on him. This was the worst possible scenario for Spider-Man -- his old villain had him dead to rights. "Luckily" for Spider-Man, Kraven only used a tranquilizer on him and buried him alive, while Kraven took over his identity (as he had proven he was the best hunter, he was now going to show that he was a superior Spider-Man). In "What If...?" (Vol.2) #17 (by Richard Howell and Marie Severin), however, Kraven still buried Spider-Man, but actually killed him first.

The Human Torch, Daredevil and Captain America teamed up to help find the real Spider-Man, but while they successfully captured Kraven, it was too late for Peter. Mary Jane Watson, however, became obsessed with the world knowing that Kraven was not the real Spider-Man, but that Peter was and that he was a hero. J. Jonah Jameson fought her on it (he had been attacked by the Kraven Spider-Man, and that just confirmed to him that Spider-Man was both a threat and a menace). This ultimately led to superheroes being outlawed by the government. Mary Jane, though, steadfastly carried on, becoming an international defender of superhero rights.

7 WHAT IF...CAPTAIN AMERICA WERE REVIVED TODAY?

In the original "What If...?" series, there was an acclaimed storyline that involved Captain America being revived today. In the second series, they took on that idea once more, only as a two-part story in "What If...?" #67-68 (by Chuck Dixon, Dario Carrasco Jr. and Tim Dzon). This time, during the Avengers battle with Namor, Namor was captured, so he was not able to find the frozen Captain America and throw him into the ocean, where his icy prison melted. Instead, years passed without Captain America being around, and the Red Skull's plots to conquer the world (which Cap initially stopped) succeeded. Cap was eventually found and revived by Doctor Doom, who told Cap of how the Skull conquered the world. However, he didn't tell Cap that he had conquered the other half of the world!

Cap teams up with the remaining superheroes (calling themselves the X-Patriots) to fight back and defeat both Doom and Skull at once. Before the final battle, Spider-Man shows Cap the tattoos he received during a Red Skull "Re-education" camp he was imprisoned in. In the end, it was Spider-Man who killed Red Skull, suffocating him with his webs, but not before the Red Skull fatally shot Peter. The heroes had won, but Spider-Man would not live to see it.

6 WHAT IF...THE ALIEN COSTUME HAD POSSESSED SPIDER-MAN?

In the original continuity, Spider-Man gained a new costume during "Secret Wars" that turned out to be an alien symbiote that was trying to bond with Spider-Man. Spider-Man originally went to Reed Richards of the Fantastic Four and was able to have the connection between himself and the alien separated, thanks to a sonic attack on the symbiote. However, in "What If...?" (Vol. 2) #4 (by Danny Fingeroth, Mark Bagley and Keith Williams, in one of Bagley's first Spider-Man art jobs), Spider-Man waited just too long before going to see Reed, who was unable to separate Spider-Man and the costume.

Instead, the costume ended up leaving Spider-Man to get a new host, the Hulk! As it turned out, it had been draining Peter's life force the whole time, so when it finally gave him up, he was now an old man! Peter worked alongside Reed to try to come up with a way to stop the alien once and for all, but sadly succumbed to old age before they could do so. Ultimately, Black Cat killed the alien to avenge the death of her former lover. However, in order to get a weapon capable of killing the alien, she had to cut a deal with the Kingpin where she would agree to work in his employ for the rest of her life.

5 WHAT IF...CAPTAIN AMERICA LED AN ARMY OF SUPER-SOLDIERS?

In another rare two-part "What If...?" storyline from "What If..." #28-29 (by George Caragonne, Ron Wilson and Ralph Cabrera), the scientist who came up with the Super Soldier Serum was not killed as he was in the regular continuity. Thus, instead of Captain America being the only Super Soldier, the United States government was able to form a whole army of Super Soldiers. They quickly won World War II, but then things changed following the war and an accident where most of Steve Rogers' friends were killed, with him being the only survivor. Cap soon turned into a fascist, arguing that the Super Soldiers were the true rulers of the world.

Clint Barton and Frank Castle were Super Soldiers whose job it was to eliminate possible threats, including a shy young man who had just gained spider-powers and had become a TV personality. As it turned out, that accident was really the Red Skull taking over from Cap and the real Cap had been missing since then. He showed up in the second part of the story and helped free the world from the Super Soldiers.

4 WHAT IF...SPIDER-MAN INTERVENED FOR THE SCARLET WITCH?

During the "House of M" crossover, Peter Parker woke up married to Gwen Stacy instead of Mary Jane Watson. They had a child together named Ritchie. Peter, though, was also dealing with some mental issues, as he had taken on the identity of the Green Goblin, as well. After the "House of M" ended, things went back to normal for Peter. However, in the second story in "What If...?: Spider-Man - House of M" #1 (by Frank Tieri and Brian Haberlin), Spider-Man managed to intervene for the Scarlet Witch when she was attacked by Hawkeye. Thus, in gratitude to Spider-Man, when she turned the world back to normal, she left Gwen and Ritchie in existence.

This obviously caused trouble for Peter and Mary Jane, but the bigger issue is that it was not just Gwen and Ritchie that carried over, but also Peter's mental instability. So, as the Green Goblin, he tried to kill Mary Jane so that he could return things to normal between him and Gwen and Ritchie. In the end, though, he realized how crazy that was and stepped in front of his own glider to save Mary Jane's life, at the cost of his own.

3 WHAT IF...GWEN STACY SURVIVED HOUSE OF M?

The first story in "What If...?: Spider-Man - House of M" #1 was by Sean McKeever, David Ross and Dan Scott, and it also dealt with Gwen Stacy surviving the end of the "House of M" universe. However, in this instance, Gwen's very existence is a problem, as she is an anomaly that is wreaking havoc on the Multiverse. This is cleverly shown by characters changing looks from panel to panel (like Iron Man having different armors each page). Gwen has to be "removed" (i.e. killed).

Complicating matters is the fact that the supervillains of the world have chosen this moment to attack, as they figure there might not be another time to finally kill the heroes. During all of this fighting, Gwen decides that she has to kill herself. However, Spider-Man can't bring himself to let her die, not even if her death means the destruction of the Multiverse, so this time, he saves her, dooming everyone. Beautiful and bleak, all at once!

2 WHAT IF...THE PUNISHER KILLED DAREDEVIL?

In "What If...?" (Vol.2) #6 (by Kurt Busiek and Luke McDonnell), the Punisher accidentally killed Daredevil. Their classic initial encounter from Frank Miller and Klaus Janson's "Daredevil" still occurred, but this time, when the Punisher tranquilized Daredevil, it accidentally caused the Man Without Fear to lose his balance and fall off of a building to his death. This led to Spider-Man hunting the Punisher down to avenge his friend. During their initial battle, Punisher was forced to shoot Spider-Man.

The problem is that while Spider-Man was in a coma, his secret identity was exposed to the world and Aunt May was murdered. When Peter Parker woke up, he was none too pleased with the Punisher. He hunted him down again in a rage, but Busiek beautifully captured just how conflicted Peter was -- he wanted to kill the Punisher, but he knew that it was wrong. Ultimately, it seemed like Peter decided that if this was what he had become, he'd just as soon die, so he opened himself up and Punisher took the opportunity and killed him. A distraught Punisher then decided to die as well, but he made sure to take the Kingpin with him, as one final act of punishment.

1 WHAT IF...?: AGE OF ULTRON

In each issue of the "What If...?: Age of Ultron" miniseries, it told a different way that the "Age of Ultron" could have gone, typically spotlighting a different Avenger in each issue. In the second issue (by Joe Keatinge, Ramon Villalobos and Ruth Redmond), Tony Stark is corrupted and his technology has taken control of the world (Ezekiel Stane took control of it all). Wolverine is one of the few heroes out there still fighting the good fight. He finds out that there is a chance to end it all, so teaming up with a new Ghost Rider (just a little kid), he seeks out more help, eventually finding Peter Parker, a retired Spider-Man, who is just an average guy with a wife and family.

Spider-Man's sense of responsibility is too great to turn Wolverine down, though, so he helps him stop Stane at his headquarters in the Savage Land. In the end, Spider-Man sacrifices himself by unplugging the Iron Man armor that powers everything, even though he knows it will cause a power surge that will kill him. In his dying words, "You know what I always say, 'With great power...'" Keatinge and Villalobos did a great job making Peter seem like a normal guy, with a death that took on that much greater power.

What's your favorite Spider-Man "What IF...?" story? Let us know in the comments section!