ok well according to my research (references are Plants vs Zombies, and Diary of a Minecraft Zombie) a zombie is someones whos brains have fallen out from playing too much video games
I do believe I have seen some kid zombies at school, their eyes have glazed over and they look wired from staying up all night playing video games, and they cant seem to learn anything.
the remedy is to go outside get some fresh air and/or plant more plants. The plants serve to oxygenate the air and that is good for brain rejuvenation