Man, Shane was the worst, right? Bitter, angry, and willing to abandon people he deemed a liability, he became the biggest liability himself. Rick finally killed him at the end of season two, with Carl having to save his dad from the reanimated Shane right after. But in the comics, the world was rid of the jerk much earlier. Shane's insanity began almost immediately after Rick found the group, but instead of Rick taking him out, it was Carl. When Shane tried to murder Rick, Carl shot him in the neck and killed him. Rick only took out the walker version of his old friend.