DC Comics’ Flash has a way to theoretically take on Marvel’s Magneto, likely leading him to brutally destroy the mutant. While the X-Men have typically struggled to take him down, the Flash could manage to win pretty easily.
Fans have frequently pointed out echoes between the Marvel Universe and the DC Universe, often citing characters with similar powers. Most of the time, overlapping heroes and villains tend to be the product of coincidence. Just as Magneto possesses the ability to control metal objects, Doctor Polaris has the power to do the same. The DC counterpart supervillain shows off what he can do with mixed results in Flash Vol. 2 #135, written by Mark Millar and Grant Morrison with art by Paul Ryan, inks by John Nyberg, and colors by Tom McCraw.
When Wally West AKA the Flash goes up against Doctor Polaris, he reveals an ability he could use against Magneto. By applying kinetic energy to the villain, he inverts his power, initiating metal scraps to fly toward him. In theory, the Flash can use Magneto’s powers to control metal against him, by literally reversing his every move. In the issue, Wally recounts how he was able to deliver the final blow, saying, "Every speedster on the planet draws their power from an extra-dimensional energy force called the Speed Force. Over the years, I've learned how to impart these energies to others... Doctor Polaris turned into a super-magnet and provided the most dramatic result so far..."
While DC and Marvel haven’t had many crossovers in recent years, Wally’s takedown of Polaris sparks an idea of what he could do to Magneto if universes collided. However, Flash goes onto reference X-Men comics, implying that in this iteration, Marvel is just a comic book publisher. If Wally jumped into their universe, there would be some additional explaining required. As he mocked Polaris, he said, "You forgot to mention how you and your Brotherhood of Evil Mutants would rule the universe for a thousand years."
The clever use of his powers also speaks to one of the Flash’s best qualities: his scientific reasoning. Whether it is Wally West or Barry Allen wearing the red tights, their creative use of the Speed Force citing real world science emphasizes the thing that makes them special as superheroes. Ironically, Barry references reading science journals earlier in the same issue as a way to brainstorm ways of taking down his rogues. By that logic, it’s plausible that the Flash learned from actual X-Men comics what might work against his version of Magneto in the DC Universe.