The X-Men keep mutating back into the culture. The Marvel superheroes, created by Stan Lee and Jack Kirby, debuted in 1963 and have spent the last 60 or so years appearing in thousands of comics, some leather-heavy blockbuster movies, 64-bit video games and the occasional animated show — the latest of which, “X-Men ’97,” premiered on Disney Plus on March 20 and is now four episodes into its season. Characters such as Wolverine, Cyclops, Storm, Gambit, Jean Grey, their leader Professor X and others — and villains like Magneto and Apocalypse — have become pop-cultural touchstones.