I was very bored one day Flipping through the channel and found something interesting There are already poisons out there that can temporarily turn people zombie (With out the craving for flesh) All some one would need to do is invent some kind of parasite or bacteria that clouds the persons frontal lobe (The part of the brain that allows reason and logic) And the brain Would just want to feed and feed even if that means attacking other humans please visit this page.
http://www.cracked.com/article_15643_5-scientific-reasons-zombie-apocalypse-could-actually-happen.html
http://www.cracked.com/article_15643_5-scientific-reasons-zombie-apocalypse-could-actually-happen.html