Here's one that takes its cue from a minor classic. No, I don't mean Le Morte d'Arthur. I mean Iron Man #149-150 in which Iron Man and Doctor Doom do battle in Camelot. Let's get medieval!
What If Vol.1 #33 (June 1982)
Based on: Iron Man #149-150
The true history: Iron Man and Doctor Doom are sent back in time to Camelot. They return by working together, cannibalizing their respective armors to build a time machine.
Turning point: What if Doctor Doom broke his word?
Story type: New World Order
Watcher's mood: A little drunk
Altered history: Perhaps more realistically, Doctor Doom betrays Tony Stark and sends himself back to the future, while stranding Iron Man in Camelot with his armor in pieces.
And... wasted? Oh Tony. Maybe you'd have more luck repairing your stuff if you weren't hitting the mead so hard.
Though he can't build a time machine out of what's left, he can still kick barbarian ass on partial power. Doing so gets him an invitation into the Round Table, as Sir Anthony of Iron is born!
Soon, Tony Stark is enjoying himself wenching and fighting back Viking raids. But Morgana Le Fay and her mama's boy Mordred continually scheme his downfall. And setting a battle during an eclipse so Tony can't draw solar power, they strike! With cheesy "evil" armor and a dagger made from a piece of Excalibur. While Tony is busy laughing at the former, he is downed by the latter!
He's rescued by retreating knights as Mordred's forces take the fight to the castle. And then the Tony Stark of the 80s becomes the Tony Stark of the 2000s by, get this...
...re-enacting the history of technology in two weeks!!! Move over Hank Pym, I think we got a new Scientist Supreme. He puts an end to the siege, but not before destiny has Mordred and Arthur die at each other's hands. But destiny makes a whiplashing double-take when Arthur names Tony as his successor.
So there you have it. Tony Stark becomes king and uses his armor to completely destroy history. Not that those generations couldn't have used a thousand years of peace, you understand, but I'm pretty sure it means the end of that particular Marvel Universe.
Books canceled as a result: Iron Man can be rebranded as a sword and sorcery series, but as of that last panel, the rest have to go. Temporal Prime Directive, Tony! Remember that!
These things happen: Though there have been several sequels to the original story (Iron Man #209 and 250, as well as Legacy of Doom), none of them end with Tony Stark living out his days in Camelot.
Next week: What if Elektra Had Lived?
My guess: We'd have a What If story called What if Elektra Had Died?