One of the first instances of walker-flavoured suicide we get in the show comes in the second season, as Andrea and Daryl are searching for Sophia, where they come across a walker hanging from a tree. The walker is guessed to have been a man who - once bitten - decided to hang himself and not live through zombification, but what happens to him is much darker. Not only does he turn whilst dangling from the neck, but the majority of flesh from his legs is missing, presumably eaten by other walkers who got to him before he joined their ranks.
14. Fence Walker
Another contender for the most stomach-churning creature on the show, this eye-popping member of the prison herd is really determined to get a snack. Situated right at the front of the herd, this walker is pushed forward, with his head mashed against the mesh, which cuts through his skin and makes his eye pop out of his skull. It's a split second image, but one which reiterates how relentless the undead are. As an aside, look at how astoundingly un-zombie-like the woman in the left of the picture is, surely she's just unhappy, not undead.