Enchant creature Enchanted creature gets -1/-1 and is a black Zombie in addition to its other colors and types.
The body dies in stages. First the skin, then the muscle. The brain is last, much to the victim's dismay.
Official Rulings for Ghoulflesh
5/1/2012 : If Ghoulflesh causes a creature to have 0 toughness or have damage marked on it equal to or greater than its toughness, it will be a black Zombie (in addition to its other colors and types) when it dies.