In order to understand the concept behind the creation of Walk Over Evil Powder, one first needs to understand the importance of foot-track spells in African-derived folk-magic. In the sub-set of the tradition known as direct foot-track magic, A person bent on doing ill can powerfully affect another by laying a trick that caused them to step upon or walk across something evil, such as Crossing Powder; powdered rattlesnake skins, buried nails, pins, or stones laid in an "X" pattern; Goofer Dust; or Hot Foot Powder. The injuries caused by malevolent foot-track magic range from general runs of bad luck and mental disturbances to unnatural illnesses and deadly medical problems. The victims of such magic are said to be "hurt" or "poisoned through the feet."
If you suspect that someone is trying to mess you up by laying tricks for you to walk over, you can protect yourself sprinkling a pinch of Walk Over Evil Powder in each shoe, or by applying Walk Over Evil Powder to the soles of your feet.