[timone317]

Have there been any major story arcs where all the heroes and villains switched sides?

[trebleshot]

If you mean they all started off as heroes and then became villains (or vice versa), then nothing comes to mind. I'm not saying no one has done it yet - I just can't recall any offhand.

There have been several times where the hero/villain roles are reversed, but they started off like that rather than evolving into it. And they usually take place in alternate realities/dimensions (What If?, Elsewords, etc). DC's Crime Syndicate of America is a great example of this.

[timone317]

I'm talking about something similar to the "What If" comics...sort of a mirror image of Earth-616. Example...the X-Men are a group of mutant supremacists and it's up to Magneto to simultaneously oppose their radical methods and prove to the world that mutants can be good.

[trebleshot]

I can't think of anything in-continuity for Marvel along those lines. The "What If...?" series is about as close as Marvel gets to something like that.

[Ender7]

I wouldn't say "ALL" but in Superior Spider-Man obviously Doc Ock has taken over spiedy's body, and now if the cover is to be believed he and the sinister 6 are taking on Venom (Flash Thompson) So Anti-Hero Spidey, and the sinister 6 (Bad/good?) vs Venom (Good)

Crazy!

[trebleshot]

Stupid is more like it (I personally can't stand that story arc).

And doesn't really fit his request anyway. Plenty of heroes/villains have switched sides individually over the years. I think he was looking more for a "Mirror Mirror"-type of story.