I have often thought this when I'm in the city. I see them bumbling along with that deadpan expression, their fat lips hanging slightly ajar upon their moon face as they struggle to breathe whilst walking at a slow pace. They always slouch, throw their body from side to side whilst they walk... their thighs struggle to move past one another... their fupas hang out of the bottom of their ill fitting shirts. Half the time you can't tell if it's a man or a woman that you're actually looking at... Yeah... I am fairly sure we are already living in a zombie apocalypse, because they are absolutely brain dead and half rotting already.  They are literally already walking putrefaction. No need to animate the dead, when we have living bodies already rotting!