At the beginning of MULTIPLE MAN, a team of X-Men discovered a single duplicate of Jamie Madrox still alive and locked away in a vault. He'd somehow survived the original Madrox's death, but was on the verge of death. He convinced Beast into creating a medicine that would save him from the M-Pox that killed the rest of the Multiple Men -- and then jumped forward in time to get Beast's cure after it had been created.
After all, this dupe was on the verge of death. He wouldn't survive long enough for Beast to create a cure. But if he went into the future after Beast created the cure, then it would be easy enough for him to survive and move on.
Except that somewhere along the way, Madrox started multiplying out of control. He and his duplicates had defeated Earth's other heroes and enslaved humanity.
Except that not all of the duplicates were unified. A few of them were virtuous enough and independent enough to get recruited into a resistance force -- led by the new Jamie Madrox Prime. He concocted a plan to send five of the duplicates into the timestream to acquire enough power to defeat the Multiple Men.
Which led to the creation of a Hulkish Madrox and a magical Madrox and a Cable-like Madrox and a Deadpool/Wolverine-like Madrox. The army of Multiple Men proved too powerful for Jamie Madrox and his super-Madroxes. He eventually sacrificed his life in order to defeat the army. Thus, Jamie Madrox met his demise yet once more!
Except that Jamie Madrox had sent five Multiple Men into the timestream. Not four. It was easy to forget the fifth Multiple Man, but he ultimately returned from his failed mission to acquire Iron Man's powers. Fortunately or unfortunately, this Multiple Man arrived in the midst of the MARVEL SWIMSUIT SPECIAL.
That means that all of the heroes were chilling out on the beach. There were no powers to acquire. Just a bar to run and heroes to serve -- something that Jamie Madrox was more than prepared to do!
He eventually returned to the present and this Jamie Madrox is the newest Jamie Madrox Prime. Return to status quo!
By the way, I remember reading the MARVEL SWIMSUIT SPECIAL back in the early 90s. It was a great experiment. No story. Just a bunch of full-page pics of superheroes in bikinis and speedos!
Incidentally, here is a pair from the MARVEL SWIMSUIT SPECIAL: Northstar and Hector (from the Pantheon) chilling alone together. Nowadays, there are so many LGBTQ heroes in the Marvel Universe. It's hard to remember a time when there were only two openly gay heroes running around!