The X-Men have no shortage of powerful mutants who wouldn’t break a sweat if they were somehow pitted against the Xenomorphs from Alien, though there is one mutant in their ranks (who may physically be the strongest) that wouldn’t survive that particular crossover–and X-Men’s darkest era proves it.
When Marvel Comics acquired the rights to publish Alien comics, the publisher released a number of variant covers depicting Marvel’s toughest heroes and villains going toe-to-toe with Xenomorphs. While these images weren’t meant to be taken literally and were simply a celebration of Alien’s new era under the Marvel banner, it did pique the interests of fans who wouldn’t mind seeing a legitimate crossover–especially given that DC already had Alien crossovers many years ago. Back when Alien was still being published by Dark Horse Comics, Dark Horse and DC did a few crossover storylines that featured the likes of Superman and Batman battling Xenomorphs–and they were a huge hit with fans. So, with Alien being published by Marvel Comics, Marvel could do a crossover without having to work with another publisher, and Marvel would be going into it with the knowledge that fans want Xenomorph/superhero crossovers. With this, plus the tease of those initial Marvel/Alien variant covers, it seems as though it is only a matter of time before the X-Men are going to battle Xenomorphs on-panel–and that will be very unfortunate for at least one of them.
In Generation Next #1 by Scott Lobdell and Chris Bachalo, a new wave of X-Men recruits are training with Colossus and Shadowcat who are acting extra violent with them in an effort to prepare these new mutants for the cruelty of this world. This comic takes place within the Age of Apocalypse timeline, so those who choose to be X-Men are less of mutant superheroes and more of freedom-fighting warriors who will more than likely die on any mission they go on. Because of this grim fact, their training must be incredibly intense, verging on cruel–though the trainees are just as prepared for these brutal matches as the trainers themselves. For example, one of the new mutants named Paige Guthrie blasts Colossus with a spray of acid, and Colossus screams out in agony only to be saved by the intervention of Shadowcat–implying that the acid was enough to take him down.
Colossus has a Weakness to Acid & Wouldn’t Stand a Chance Against Xenomorphs
As Alien fans are well aware of, Xenomorphs have acid for blood which acts as the Xenomorphs’ perfect defense mechanism against predators. Colossus’ mutant power is the ability to cover his entire body in metal on command, which makes him invulnerable to attack in most situations. However, when he was sprayed with acid in this issue of Generation Next, he was covered in his techno-organic metal and still felt the sting of the acid–a pain that was strong enough to completely take him out of the fight, leading one to conclude that if he kept getting sprayed with the acid, he would have eventually been killed.
So, even though Colossus is easily strong enough to crush an entire horde of Xenomorphs single-handedly, his weakness to acid (as established in this comic) means that he’d be taken out by Alien’s iconic monsters pretty quickly–proving that Colossus, who is perhaps the strongest X-Men member, wouldn’t survive the seemingly inevitable Marvel/Alien crossover.