House of M

"No more mutants."

A Marvel Comics Miniseries with several tie-in books following the events of Avengers Disassembled.

Wanda Maximoff, better known as the Scarlet Witch, suffers a reality-warping mental breakdown and is taken to Genosha by her father Magneto. When Wanda shows little sign of recovery, the X-Men and the Avengers meet to discuss what action should be taken next; they decide that Wanda must be killed. The combined teams arrive at Genosha when suddenly the world is swallowed by a bright white light...

The scene cuts to Wolverine as he wakes up in a world that has completely changed: A world where mutants are the dominant species, humans are now a persecuted minority, and the United States is led by the House of Magneto. The now-scattered and mind-altered Avengers and X-Men must try to reunite and find out how to reverse what happened on the day they arrived on Genosha. They later come across Layla Miller, a young girl who is aware that reality has been changed and who helps expose the truth about their "current" reality.

Turns out Wanda's twin brother Pietro (Quicksilver) convinced her to rewrite reality into one where all the heroes got to have their greatest desires -- including Magneto's and Professor Xavier's -- which meant that Magneto's family ruled the mutants and the mutants ruled the world, and that Professor Xavier had died a meaningful death and mutants and humans live side-by-side (sort of). The Avengers and the X-Men confront Wanda after regaining their memories of the reality that existed before Wanda's Cosmic Retcon. Wanda suffers another nervous breakdown and eventually restores the original reality, but depowers 99.99% of the world's mutants as well. Afterwards, she disappears without a trace and the reader is given a clue that the depowering might not be as permanent as it seems.

The House of M storyline is continued in X-Men: Decimation.

The next Marvel Comics Crisis Crossover is Civil War, followed by World War Hulk.

Tropes found in the comic:
"Wanda: No more mutants."
 * Alternate Continuity: The entire "House Of M" reality is a short-lived one.
 * Back From the Dead:
 * Be Careful What You Wish For: The Aesop of some of the tie-in miniseries. For instance, Doctor Doom managed to get almost everything he claimed to want: his mother alive, his face unscarred, Richards dead -- and he manages to lose it all, mostly at his own hands, by the end of the Fantastic Four: House of M miniseries.
 * Calling the Old Man Out: Wanda to Magneto.
 * Continuity Porn: When Layla unlocks Peter's memories, we get a two-page spread of the notable villains and events of Spidey's life.
 * Cosmic Retcon
 * Crisis Crossover
 * End of the World Special: Wanda. Twice.
 * Fleeting Demographic Rule: The Avengers went through a much more drastic reality warp caused by Morgan Le Fay only a few years earlier, and they reacted to that one almost as if it were routine, because they've been through so many similar incidents before. This time around, everyone acts as if they've never seen anything remotely like this, and they're all on the verge of stark panic.
 * Godwin's Law Of Reality Warping
 * Hero of Another Story: Captain America. In this reality, he was never frozen in ice and got to continue his life post-war. He only cameos in the main mini-series as an old man (prompting the other heroes to just leave him be), but a tie-in issue of his own comic summarizes the different things he experienced during the intervening decades.
 * Per her own desires, Ms. Marvel had managed to achieve widespread fame and acceptance as a hero in the House of M reality, even though she was explicitly a non-mutant.
 * Heroic BSOD: What kicks off the event (arguably, the entire event takes place within Wanda's blue screen).
 * Indulgent Fantasy Segue: A tragic one at the beginning when Wanda gives birth to her twin sons while surrounded by her friends and family... only to be forcefully pulled out of her fantasy by Professor X
 * La Résistance: The Human Resistance Movement, led by Luke Cage
 * Lotus Eater Machine: Wanda's altered reality is this for the entire Marvel Universe. All the heroes who could oppose her are given new lives doing what makes them happy, partly because it's what Wanda wants, partly to keep them from rebelling and trying to change reality back.
 * Nice Job Breaking It Hero: The greatest example ever, since the world that Wanda creates is a haven for mutants and humans, a perfect world for everyone (except maybe Wolverine) and Professor Xavier has explicitly said many time that he would be willing to die if it meant that his dream of a perfect world where there was peace between humans and mutants came to pass. So the "heroes" wreck this perfect world that Professor Xavier would be more that willing to accept, and give Wanda a nervous breakdown and destroy this paradise to do exactly what Xavier would not want.
 * It's not "perfect" for everyone. Humans are outright discriminated against, and though its not as bad as it often gets in the regular verse for mutants it is worse in one sense in that it is enforced by law; Spider-Man has to go on the run when the world finds out he isn't a mutant (though this has more to do with him being exposed as lying about having been a mutant). Magneto isn't the only ruler either as he allows the likes of Apocalypse and Doctor Doom to have their own territories; the former has outright slavery and the latter has made the Thing his mindless "pet" after the rest of the Fantastic Four died. Both actively scheme against Magneto too, so the world could swiftly take a darker turn. Not to mention that even if everything is better on the whole Wanda is still a mentally unstable threat to the Multiverse (this event alone actually caused it severe damage) and this whole thing could have crashed at any moment without the heroes learning anything. Especially when you consider the hints that Wanda was subconsciously helping them and sabotaging her own universe, and in the end decides she hated it.
 * Nice Job Fixing It Villain: Alter reality & give everyone what their deepest desires. Even the guy who's deepest desire is that his Laser Guided Amnesia be undone, so he'll remember his entire life again... Even the fact that you've just gone & altered reality. Oops.
 * Not Quite Human: The mutants, obviously.
 * Oracular Urchin: Layla Miller. Also a MacGuffin Girl.
 * Reality Warper: The Scarlet Witch
 * Ret Gone: In-story example with and
 * In the latter's case, actually, only Ben becomes an irrational version of the Thing (which Dr. Doom refers to as "It") and Johnny goes on to become an underground mecha fighter, like Tony Stark and his dad.
 * Ripple Effect Proof Memory: Ironically, Wanda's Lotus Eater Machine effect gives Wolverine this as a side-effect of his wish to remember everything.
 * Roaring Rampage of Revenge: Initially averted. After finding out that the reality shift has, Spider-Man tells Wolverine he's going to kill the Scarlet Witch. Wolverine says that he won't give Spidey the chance.
 * Played straight.
 * Status Quo Is God: Played stright & averted.
 * "No More Mutants" - Averted, in that a large number of mutants are depowered & the X-Men underwent a massive shift in their position in the Marvel universe because of this. Played straight, with most of the 98% of mutants who lost their powers being unknown to the reader, and the majority of the named characters being C-List characters or lower with the big name mutants retaining their powers - Really, the only major mutant characters who lose their powers are, and even then, it's only temporary.
 * Character Development - Averted, Wolverine rembering everything he'd previously forgotten. Played straight, in that despite the Trauma Conga Line he goes through during the story, there are no lasting effects for Peter Parker & his memories of the "House of M" timeline are never mentioned again.
 * Superior Species  convinces Wanda to rewrite reality using this as one of the excuses. She's thoroughly disillusioned about it by the end, though.
 * Villain World: The premise, though it's presented as a (semi-)benevolent dictatorship. Magneto is now the ultimate authority, with smaller territories being delegated to less-scrupulous villains like Apocalypse and Doctor Doom). Mutants have it much better than nonmutants, who are distinctly second-class citizens.
 * Wham Line:


 * Wistful Amnesia: Former superheroes reverted to ordinary humans have a lingering sensation of loss. It doesn't help that mutants rule the world, leaving the powerless to languish in a state of depression called "Dead End Syndrome."
 * With Great Power Comes Great Insanity