The only reason why zombies exist is because Chuck Norris believes that some people deserve to die twice from his roundhouse kick. Of course, as it is known, Chuck Norris's roundhouse kick is the most effective method of severing the zombie's brain stem connection to the rest of the body, therefore putting the undead down for good. Upon first meeting a zombie, Chuck Norris is known to have said: "You only live twice" - which he licensed as a title to the then-upcoming James Bond movie, but out of fear, no roundhouse kick was featured in said movie - not only not to anger Chuck Norris, but also not to look like a fool because nobody can roundhouse-kick like Chuck Norris except Chuck Norris himself!