The end of the Secret Empire crossover also brought an end to one of the most controversial plot twists in the history of the Marvel Universe. In 2016, Captain America: Steve Rogers #1 (Nick Spencer, Jesus Saiz) shocked the world with two words: "Hail Hydra." As Captain America said those words, it was slowly revealed that his history had been changed to make him a Hydra sleeper agent. With Secret Empire #10, Hydra Cap has been defeated and the original Captain America restored, but the impact remains. Comic book readers were divided on the twist, some calling turning Cap into a fascist the worst plot twist in Marvel history. But it wasn't. Not by a long shot.

RELATED: 15 Superhero Movie Twists That Blew Our Minds

Over the years, Marvel has done some pretty crazy plot twists. Some have been awesome and others not-so-good. Some of the worst plot twists have come and been accepted unhappily by the readers. Other plot twists have been so hated or controversial that Marvel went to a lot of trouble to reverse them out of continuity. In the interest of putting Hydra-Cap into perspective, CBR decided it's time to run down Marvel's plot twists that were considered the worst ever.

15 WOLVERINE IS A LUPINE

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Wolverine is one of the most popular and fiercest superheroes in the Marvel Universe, a mutant whose healing factor allowed him to survive a process that bonded his skeleton with unbreakable adamantium. At least, that's how his origin has been described until 2007's Wolverine #53 (Jeph Loeb, Simone Bianchi).

That's when Wolverine met a supervillain named Romulus who turned out to have secretly planned every horrible thing that ever happened to Logan. See, Romulus was part of a species that evolved from canines instead of primates called Lupines, and said Logan was a Lupine, too. The idea of Wolverine being a Lupine instead of a mutant didn't make much sense, leading to a reversal in 2012's Wolverine #312 (Jeph Loeb, Simone Bianchi). Romulus’ sister Remus basically told Wolverine her brother was lying, and everyone just tried to forget it.

14 ONE MORE DAY

One of the few bright spots in Peter Parker's life has been his relationship with Mary Jane. That's why 2007's "One More Day" (J. Michael Straczynski, Joe Quesada) crossover triggered so much controversy. In the crossover event "Civil War," Parker's Aunt May was shot and left on the verge of death. Spider-Man, desperate to save his beloved aunt's life, agreed to a deal with the supernatural villain Mephisto. In exchange for saving her, Mephisto altered history so Parker and MJ were never married.

While the idea of getting rid of one of Marvel's most beloved marriages was enough to get fans upset, the outcome was even less loved. It was hard to figure out what storylines still existed, much less how to explain their history without MJ. That may be why Marvel created Spider-Man: Renew Your Vows, a series set in an alternate reality where the couple stayed together.

13 XORN IS MAGNETO

Magneto taking off Xorn's helmet and telling Xavier the dream is over in New X-Men #142

In 2001's New X-Men Annual #2001 (Grant Morrison and Leinil Francis Yu), the X-Men first met Xorn, a mutant who supposedly had a literal sun in his brain. Forced to wear a mask to contain his energies, Xorn joined the X-Men and became a faithful member until he revealed he was their archenemy Magneto in disguise. Magneto went on get his head cut off by Wolverine.

It was a shocking twist. Maybe a little too shocking. The problem with Magneto pretending to be a star-headed mutant was that some fans actually liked Xorn and wanted him back. Others wanted Magneto to still be alive. Marvel had to introduce a complicated story where Xorn had a twin brother who just pretended to be Magneto, and Magneto and the real Xorn were still alive.

12 THE CLONE SAGA

Peter Parker fights his clone in Marvel Comics' Clone Saga

In 1994, Marvel introduced the controversial storyline that came to be called the Clone Saga. In the story, Peter Parker discovered that a homeless man was a clone who had been introduced back in the 1970s. He returned as Ben Reilly, claiming to be the real Peter Parker, and Parker was horrified to discover that medical tests showed he was actually the clone.

Spider-Man had an identity crisis and fans were shocked that decades of continuity had been retconned into a lie. Ben Reilly was introduced as a replacement for Parker to become a Spider-Man without all the continuity hanging off of him while Parker lost his powers and Reilly settled into his place. Unfortunately, fans didn't take to the idea, and the Clone Saga ended by reversing out everything to put Peter Parker back as Spider-Man again.

11 GWEN STACY'S CHILDREN

Green Goblin Seduces Gwen Stacy

Gwen Stacy was Peter Parker's long-suffering girlfriend until 1973's iconic The Amazing Spider-Man #121 (Gerry Conway, Gil Kane) when the Green Goblin hurled Stacy off of the Brooklyn Bridge. Her death was a shock to the fans, but a bigger shock lay in store for them. In 2004, writer J. Michael Straczynski wanted to introduce a set of adult twins as Parker's kids, but the editors thought that would age Parker too much to have full-grown children.

That's where The Amazing Spider-Man #509 (J. Michael Straczynski, Mike Deodato Jr.) came in with the "Sins Past" arc. It turned out that Stacy had an affair with the Green Goblin and secretly gave birth to twins Gabriel Stacy and Sarah Stacy whose mutated blood caused them to become adults and grow up to hate Spider-Man.

10 THE CROSSING

Moments in Iron Man's life from The Crossing from Marvel Comics

In the 1995 story "The Crossing," the Avengers were trying to find a killer, only to discover the murderer was one of their own. In Iron Man #319 (Terry Kavanagh, Tom Morgan), Tony Stark revealed he had been secretly working with the time-traveling supervillain Kang the Conquerer for decades. In order to stop him, the Avengers went back in time to bring a teenage Tony Stark back to the present to stop the adult Iron Man, leaving teen Stark to take over.

The whole storyline was intended to make a teenage Iron Man in the mainstream Marvel universe, but turning Iron Man into a traitor didn't sit well. In a later storyline, it was revealed that Kang was really another supervillain Immortus, and adult Stark was merged with teen Stark to put everything back to normal... sort of.

9 NIGHTCRAWLER THE DEVIL

Azazel dumps Mystique Uncanny X-Men

Created by Len Wein and Dave Cockrum in 1975's Giant-Size X-Men #1, Nightcrawler's mutant power to teleport came with a devilish appearance. With black skin, fangs, pointed ears and a spiked tail, he was an outsider his entire life. It was always said that Nightcrawler was found as a baby by a gypsy and raised in the circus. That all changed in 2003 with Uncanny X-Men #428 (Chuck Austen, Shawn Phillips) where it was shown that Nightcrawler's father was Azazel, a demon.

Well, to clarify, Azazel is from a race of demonic-looking creatures called Neyaphem who are trapped in a hellish Brimstone dimension. He fathered Nightcrawler with the mutant Mystique to try to return to Earth, which he claimed to be the ruler of. The "upshot" is that Nightcrawler went from a deformed mutant to the son of Satan in one issue.

8 SHE-HULK SLEEPS WITH JUGGERNAUT

She-Hulk is a superhero with super-strength who's hooked up with a lot of people in the Marvel universe. That's mostly because she's a beautiful green woman with a great personality. One of her most controversial conquests came in Uncanny X-Men #435 (Chuck Austen, Ron Garney) when she was defending the Juggernaut, and actually went to bed with him. The idea of She-Hulk sleeping with an invulnerable supervillain, especially one with the history between him and the X-Men, and one who she was defending in court, just didn't make a whole lot of sense.

In later issues, people kept bringing up Juggernaut, with She-Hulk insisting that she never actually slept with him. Finally, in She-Hulk #21 (Dan Slott, Ty Templeton, Rick Burchett), She-Hulk met an alternate version of herself who admitted she had done it, making the incident a big misunderstanding.

7 QUICKSILVER AND SCARLET WITCH "IN LOVE"

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In the Ultimate Marvel universe, all the rules were thrown out the window. The characters were also allowed to say and do things that they couldn't in the Marvel universe since the Ultimate universe was an alternate reality. Captain America was kind of a jerk, Spider-Man was half-black and the children of Magneto were very close. Very, very close.

Quicksilver and Scarlet Witch have always been close because they're brother and sister, and because they often worked together on the Brotherhood of Evil Mutants and later the Avengers. In Ultimates 3 #1 (Jeph Loeb, Joe Madureira), things went further with the revelation that they loved each other, not as siblings but as man and woman. Captain America was shocked by that plot twist, and so were the readers.

6 EVIL THOR CLONE

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In 2005's Civil War, the US government passed the Superhero Registration Act, a law that required all U.S. superheroes to register their real identities with the government. While some superheroes like Iron Man supported the law, Captain America and other superheroes opposed it. The conflict turned into a literal war between the two sides.

To build up his forces, Iron Man revealed in Civil War #3 (Mark Millar, Steve McNiven) that he used cloned cells from Thor to create a duplicate of the god of thunder named Ragnarok. Fans weren't aware that gods could be cloned. As bizarre as it was to see a clone of Thor attack the superheroes, Ragnarok punched a hole in the chest of Goliath, killing one of the few popular African-American superheroes in the process.

5 QUICKSILVER AND SCARLET WITCH AREN'T MUTANTS

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Right now, Marvel has kind of a problem with mutants. It doesn't own the movie rights to the X-Men, so its comics serve as free advertising for Fox. That may be why Marvel has been putting less emphasis on the mutants in its comics recently. A perfect example of that is what happened to Quicksilver and Scarlet Witch.

The Maximoffs have been mutants since their first appearance as members of the Brotherhood of Evil Mutants. Later on, it was established that they were children of the Brotherhood's leader, Magneto. Yet in Uncanny Avengers #4 (Gerry Duggan, Rick Remender, Daniel Acuna), the High Evolutionary revealed that he had experimented with them as children, giving them their powers. To change decades of continuity allegedly over a copyright dispute didn't make fans happy.

4 MS. MARVEL'S SON/LOVER/ATTACKER

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One of Marvel's darkest moments came in 1980 with the bizarre 200th issue of Avengers. In the issue, Ms. Marvel discovered she was pregnant and gave birth in just three days with no clue who the father was. Not only did the baby come out quickly, but it grew rapidly to become a full-grown man within the same issue.

Naming himself Marcus, he reveals he was created in an alternate dimension called Limbo by the supervillain Immortus. Marcus brainwashed and impregnated Ms. Marvel so he could escape and be born into our world. Besides the ickiness of having Marcus becoming his own father by having sex with his mother, there's the fact that Ms. Marvel was raped. Worse than all that, Ms. Marvel somehow fell in love with Marcus and left to his dimension. Fans were rightfully outraged by the story.

3 NO MORE MUTANTS

no more mutants scarlet witch

Since their creation in 1963's X-Men #1 (Stan Lee, Jack Kirby), mutants have become one of Marvel's favorite creations. Instead of having to come up with origins for people with superpowers, all writers had to do is say "he/she is a mutant" and they could move on to the good stuff. That's why, at the end of 2005's House of M, Scarlet Witch said "no more mutants" and depowered over 99% of the mutants on Earth.

At least, that was the idea. To fans, what started out as a bold plot twist to reduce the Marvel universe's dependence on mutants became a mess. There was confusion over which mutants still had their powers and why some depowered mutants kept their physical mutations while others didn't. Over time, the number of powered mutants has grown, making "no more mutants" less than accurate.

2 SUPERIOR IRON MAN

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If there's one plot twist comics love, it's turning superheroes into supervillains. With 2012's Superior Spider-Man story arc, Spider-Man's archenemy Doctor Octopus switched minds with Peter Parker, leaving Peter to die in his body. Yet Doc Ock ended up becoming a hero on his own as Superior Spider-Man, so Marvel tried Superior Iron Man.

In the Axis crossover, when the Scarlet Witch cast a spell that turned supervillains into superheroes, it also caused Iron Man to turn evil. Afterwards, Iron Man managed to keep her from reversing the spell on him. Superior Iron Man #1 in 2015 (Tom Taylor, Yildiray Çinar) showed Tony moving to San Francisco and becoming a mob boss with a smartphone app. Not all fans were on-board with the new Tony, which may be why he was killed when 2015's Secret Wars reset the universe.

1 SHADOWLAND

In 2010, the "Shadowland" crossover came to the streets of New York. In earlier issues, Daredevil took control of the ninja clan known as the Hand, and returned from Japan with a new focus. In Shadowland #1 (Andy Diggle, Billy Tan), Daredevil brought the Hand to Hell's Kitchen and set up a temple/prison in an abandoned building. It seemed like Daredevil started abusing his new power by killing his enemies, including his nemesis Bullseye, so the street-level heroes like Iron Fist, Punisher and Moon Knight worked together to try to stop him.

The plot twist fans didn't care for came towards the end when it was revealed that Daredevil was controlled by the Beast of the Hand. Once again, a hero turned evil because he was being controlled by an evil force. Some fans think that's becoming a cliche in comics, with good reason.

Which one of the above do you think was the worst plot twist in Marvel history? Let us know in the comments!