Astonishing X-Men #32 (2009) Marvel comic book. The X-Men have fought towering, mutant-slaying robot Sentinels before. But never one quite like this. Never a Sentinel made of meat and bone, wearing the skin of one of their own deceased teammates, every technological aspect given a biological solution. And as the X-Men fight for their lives, they’re left to wonder: What could this monstrosity have to do with THE BROOD?