Once. It didn't end well. I fully expected at some point to have a depowered character, but what ended up happening was a extreme case of lead poisoning.
I use part of the backstory from Champions: the New Millennium where the Dr. summoned the Destroyer entity and he was merged with it during WWII and the entity keeps him alive.
I think Radar had EDM-Time Travel. It explains the comic books from the future and that he was a virgin in the later shows even though he wasn't in the first couple of seasons.
Let's add Kirby's Jimmy Olsen (though I guess it's part of the 4th world sage but nobody remembers), Kamandi (I sometimes think I'm the only fan of this), and Grell's Warlord.