WARNING: The following article contains major spoilers for Uncanny X-Men #12 by Matthew Rosenberg, Salvador Larroca, Rachelle Rosenberg, and Joe Carmagna, on sale now!
The giant, purple, mutant-hunting robots known as Sentinels have been the scourge of Marvel's mutant population since they first appeared in The X-Men #14 back in 1965. Over the decades, these persecuting automatons have undergone plenty of reiterations, and not just in comic books. From the shape-shipping, unstoppable nightmares in X-Men: Days of Future Past to the spindly, spider-like snitches from the show Gifted, we’ve seen plenty of newer, deadlier versions which operate outside the classic comic mold. Now, in Uncanny X-Men #12, we meet a new take on the classic mutant-deterrent and they might be the most horrifying versions yet.
Shortly after the recently-resurrected Cyclops and Wolverine reunite and battle throngs of foes, the duo make their way to a shady government facility where a number of their fellow teammates are being held captive. Wolverine's plan to break into the facility undetected is quickly upended, and the two frenemies find themselves ambushed by a group of Sentinels. Normally, this would be nothing new for these two; Wolverine and Cyclops have been laying waste of these murderous robots for years, after all. It's kind of their thing. But what sets this moment apart from the myriad optic blasts and trifurcated hulls Scott and Logan would have normally left scattered about the battlefield is the sudden realization of what lies beneath the robots' steely visages.
These Sentinels bleed. We're not talking about spurts of oil or some synthetic lubricant, no; this is actual blood from the living, breathing people piloting the robots. Once Wolverine takes a chunk out of one, he sees (and smells) blood on his claws and tells Scott to stand down. Now, Logan has never really been one to back down from a fight, nor is he squeamish when it comes to blood, but the horror of plunging a blade into something he assumed to be completely synthetic only to learn there's a pulpy, organic center is shocking enough to cause even Logan to proceed with caution. His devil may care attitude is usurped by the panic of what could be going on under the mechanical exterior, but what (or who, rather) happens to be producing this weird Sentinel blood is somehow more upsetting.
Once Scott and Logan remove the Sentinel outer hull, they discover Guido Carosella (better known as the unique eyewear-advocating mutant Strong Guy), who had been absconded away after contracting the Transmode Virus. Guido speaks in in the same manner as is fallen teammate Warlock and tells Wolverine and Cyclops about the horrors the O.N.E. has created. More of these mutant-core Sentinels are cracked open like walnuts, revealing Dani Moonstar and Karma, who were also infected by the end of Matt Rosenberg and Adam Gorham's New Mutants: The Dead Souls.
There's something unsettling on a primal level about a machine that bleeds actual blood (which might be the most obvious statement in this article). The union between organic and synthetic components betrays our own inherent understanding of biology and what it means to be human to some degree. Now, that isn't to say that cybernetic implants or robotic appendages are bad. Quite the contrary. But there is something horrific about the notion of forcefully altering one's humanity in order to become something automated. Once fiction starts blurring the lines between man and machine, the combination isn't the harmonious like peanut butter and chocolate. It's more like orange juice and tooth paste (if this doesn't make your skin crawl, go taste test it). Things don't mess so well. The organic attributes fight against the forced synthetic implements. It's an existential nightmare for a species who already has to deal with a world filled with hate. Now, mutants can be turned into literal monsters.