Nicholas’s body, apparently. The man who once tried to kill Glenn, and upon whom Glenn showed unusual mercy, starts to fog out again. He sees that indeed the situation is entirely hopeless. Glenn’s trying to pull him back, but it’s not working. “Thank you,” Nicholas says, before putting his gun to his temple and pulling the trigger. That’s relatively shocking, and Glenn is covered in blood. But then, Nicholas’s dead body lurches into Glenn’s, and pushes the two of them off the dumpster, into that scrum of walkers. It’s awful. He didn’t die making some noble sacrifice. He didn’t die performing some heroic deed that saved others. He dies for no good reason whatsoever, he dies because idiot Nicholas led them down a dead end; he dies because a decision to show somebody mercy (a recurring theme here) comes back to haunt him. As he lies there, getting eaten alive, blood bubbling out of his body, walkers pulling out his entrails, you can see the horror in his eyes, and maybe it’s just us, but it seemed that you could see that what was upsetting him the most (and great credit goes to Steven Yeun for conveying this) was this: I’m not getting back to Maggie.