The X-Men's Thor's hammer, Mjolnir, in one of the most epic ways imaginable to destroy her own hammer Stormcaster, realizing that it was created to manipulate her powers. Ororo Munroe proved that with great power came even more responsibility, as she unmade Stormcaster due to its dark influence.
Storm's hammer Stormcaster first appeared in X-Men: Annual #9 from Marvel Comics, where the X-Men ended up on Asgard, with Loki attempting to manipulate a then-powerless Storm. The trickster God crafted Storm an enchanted hammer that gave her powers similar to Thor's, granting similar abilities she had been missing since being depowered. But, the hero and the X-Men quickly realized that Loki had ulterior motives with the hammer and attempted to use Storm for his gain. In the end, she rejected Stormcaster and attacked him. But, when the hammer eventually returned in a later story, a worthy Storm wielded Mjolnir with Thor to destroy Stormcaster.
In X-Men To Serve and Protect #3's "Stormfront" story by Marc Guggenheim, Eric Koda, Danny Miki, Sonia Oback, and Dave Sharpe, Thor brings Stormcaster to Wakanda as he found it while sorting through Asgard's relics. Upon touching it, Storm immediately transforms into the Goddess of Thunder, which leads Thor to try to break her from the enchanted hammer's hold. Ultimately, Thor convinces Storm to grab Mjolnir with him as they swing it together towards Stormcaster, destroying the hammer and freeing the mutant from its control.
While Stormcaster would later reappear despite its destruction, Storm wielding Mjolnir alongside Thor is one of the most epic ways a hero has been revealed as worthy in the pages of Marvel Comics. However, the moment comes with a giant asterisk. There's a debate about whether Storm actually wielded Mjolnir, considering she was holding it alongside the God of Thunder when smashing Stormcaster. However, given her power, ability to wield another enchanted hammer, and her actions as a hero, it's fair to assume that Storm was worthy of the hammer, even if she didn't wield it solely by herself.
Storm's turn as the Godess of Thunder was brief, as Loki's attempts to control her with a different enchanted hammer ultimately failed. But, seeing Storm wield Mjolnir alongside Thor and smash Stormcaster proved to be an incredibly epic moment that showed when the God of Thunder eventually steps away from the role or is defeated, the X-Men hero would be a fitting replacement as a hero seemingly worthy of the mantle.
