The ubiquitous "gotta shoot 'em in the head" scenario. For many different reasons, The Undead throughout fiction are vulnerable only to Boom! Headshot!. Kinda like how (many) vampires are only vulnerable to getting stabbed in the heart. Fortunately, removal of the head also works on people who are not a member of the walking dead, so you don't have to worry about it going out of fashion as a killing method. Is a consequence of a Cranial Processing Unit. Most songs about zombies tend to Lampshade this trope. A lot of these examples should be moved to Decapitation Required.