WARNING: The following contains spoilers for Way of X #5, on sale now.
Nightcrawler isn't strictly one of the most powerful X-Men. Capable of mid-range teleportation, he can be impressive in a fight but lacks the sheer power and potential of other teleporters like Manifold or Blink. But that doesn't mean he won't push himself to the limit when he needs to -- producing some genuinely impressive results.
In Way of X #5 by Si Spurrier, Bob Quinn, Java Tartaglia and VC's Clayton Cowles, Nightcrawler pulled off perhaps the single most impressive teleportation he's ever attempted -- and ended up losing his life for it.
Nightcrawler has tasked himself with one of Krakoa's most deceptively difficult tasks: forming the basis of a mutant religion. On top of all the philosophical constraints that such an endeavor invites, it can also just be inherently difficult to help a number of mutants with very conflicted views on one another to try and overcome their conflicts. Nightcrawler finally reaches a place where he can break through to Fabian Cortez and Lost -- despite Lost's understandable fury at Cortez for having murdered her family years earlier. Things have only been made worse by the presence of Onslaught, the psionic monsters created from the darkest sides of Magneto and Xavier's psyches fusing into one being.
Nightcrawler and Legion have quietly been trying to contend with Onslaught's infection of the mutant population, and it seems the being has taken notice. Taking control of Fabian Cortez, Onslaught is able to forcibly take over his body and use his powers of mutant amplification to overload Lost's abilities. This forces her control over gravity to behave wildly, which causes the Martian moon of Phobos to descend towards the newly dubbed Planet Arakko -- threatening to wipe out millions within moments. The act even kills Lost, preventing Fabian from amplifying her again to push back against the falling moon. With no other options, Nightcrawler tells Cortez to overload his own powers. Cortez then empowers Nightcrawler to the full possible extent of his abilities.
Teleporting up to the descending moon and engulfed in flames, Nightcrawler quickly teleports himself and the falling moon away from Mars -- saving everyone on the planet all by himself. As he predicted though, the act kills Nightcrawler. He's promptly resurrected by Xavier and the Five, but it's clear that all of Krkaoa and Arakko are aware of what he did. Even if his death (and the ensuing shut down of Cortez's mind) keep him from understanding the full weight of his epiphany shortly before the act, this will likely raise Nightcrawler's clout within the Krakoan and Arakko communities. It's a truly impressive feat, even taking into account how he had an additional power boost assisting him in the act.
Nightcrawler's abilities are often limited. Even at his most impressive, Nightcrawler typically can only teleport himself and maybe one other person a couple of hundred miles -- such as when he teleported himself and Hope across multiple states to reach Utopia (despite being fatally wounded) in Second Coming. Here though, Nightcrawler teleported an entire moon within a matter of moments. In terms of both distance and mass, that's perhaps one of the most impressive single feats Nightcrawler has ever accomplished. Even if the act ultimately cost him his life, Nightcrawler's actions prove just how powerful the blue elf can really be if called upon, and how much he's willing to do to save the lives of his fellow mutants -- allies and enemies alike.