Ezra Miller in “The Flash.” Warner Bros. Pictures

In “The Flash,” the titular superhero and Justice League member who is so fast he can time travel – via something called the Chronobowl, a sort of swirling arena of temporal possibilities that he enters by, er, running really fast – attempts to return to his childhood so he can prevent the murder of his mother (Maribel Verdú). A murder that, as the film begins, his father (Ron Livingston) has been falsely accused of. It will be a simple in-and-out job. Or so Barry Allen, the Flash’s alter ego played by Ezra Miller, believes.

Barry’s world-weary mentor Batman, aka Bruce Wayne (Ben Affleck), who unlike his protégé appears to have actually seen a couple of time-travel flicks before, cautions Barry that it’s a bad idea. That’s because of the compounding impact of the butterfly effect, which holds that the smallest change made in the past – stepping on the wrong blade of grass, for instance, or causing the errant flap of a butterfly’s wing – can produce unintended consequences in the future. And it is a terrible idea, but not for the reason Bruce thinks.

It’s a bad idea because there is a more urgent need than saving Barry’s mother.

If I had a time machine, I would journey back to an era before Hollywood went completely crazy for the multiverse: before last year’s multi-Oscar-winning metaphysical mash-up “Everywhere Everything All at Once” and before 2018’s Oscar-winning animated feature “Spider-Man: Into the Spider-Verse” (which just received the sequel treatment); before “Doctor Strange in the Multiverse of Madness,” before “Spider-Man: No Way Home,” and before Disney Plus’s alternate-universe-mad Marvel spinoff series “WandaVision” and others. I would stop whoever set this misbegotten juggernaut in motion.

It’s not that “The Flash” or some of that other content is bad. The new film has it moments, thanks mainly to Miller, who brings a mesmerizing energy to dual roles: one their character’s relatively calm 30-ish self, the other a manic, teenage version of Barry he accidentally encounters while attempting to return to the present. The disconnect between Barry’s mature and adolescent selves, a running gag, can be amusing. But coming on the heels of the parade of similar content that we’ve been subjected to for the past several years in the world of superhero films and shows, the device cloys. To borrow the assessment of a stranger I happened to be standing next to in the men’s room after a recent press screening, “The Flash” is just the latest example of the out-of-control “multiple-meta-timeline bubble” – and it feels like it’s about to burst.

Michael Keaton, center, flanked by two versions of Ezra Miller in “The Flash.” Warner Bros. Pictures/DC Comics

The strain is apparent. Stranded in the past, having lost his own powers and been saddled with training his tag-along younger doppelgänger – by re-creating the lightning strike that gave him his superhuman speed – Barry embarks on a mission to rectify his mistakes. It’s a mission that leads him to seek out the assistance of Bruce, who in is this particular timeline is played by Batman franchise veteran Michael Keaton – but as a long-haired, bearded recluse who has retired from the world of crime fighting, and who now looks like a graying member of a 1970s headbanger band on its 30th anniversary reunion tour. He’s not an older version of Bruce Wayne, but a completely different person. But how can this be?

As this grizzled Bruce explains to Barry – using a bowl of cooked spaghetti and several uncooked strands as a nonsensical visual aid – changing the past alters not just the future but the past as well, thanks to something called retro-causality. It’s all a bunch of hoo-ha, but it does allow for a vision of the world to coalesce in which several things are out of whack: There is no Justice League; General Zod (Michael Shannon) – the Kryptonian bad guy from 2013’s “Man of Steel” – is once again alive and intent on world domination; and in place of Superman, who never made it to Earth, there is Supergirl. Sasha Calle is a welcome presence in the role, all super-scowl and a knockout punch.

It all culminates in the kind of chaotic, epic battle sequence of which you will by now be well familiar – perhaps even sick of – one made more incoherent by the teenage Barry’s frequent sorties back into the Chronobowl to do or undo something that might set things aright. Expect numerous, gratuitous appearances by various personages from previous DC Comics film and TV content – some released and some never made – for no other reason than fan service.

At the center of all the mayhem is Miller, who has been in the news lately for the wrong reasons: criminal charges, in addition to abuse and assault allegations. It’s an all-too-easy mistake to conflate the performer with the performance. But the troubled actor, ironically, brings to their character (or, rather, characters) an intriguing sense of duality – a split personality – that offers the film’s most accessible and intriguing interpretation of the multiverse: a man at war with himself.