In the practice of Hoodoo magic there is a type of magick called “Foot Tracks” also known as laying tricks.
This type of magic is meant to “cross” whoever crosses path with it. Victims of this magic tend to be “lost” for many years with a wandering mind, they have difficulity in gaining money and love, or more seriously “poisioned” with incureable health problems, especially leg and feet pain.
The way this is done is through the belief that roots, powders, dirt, etc. can be used to enter the body through the feet causing any number of consequences. Ideally the person will walk through the magical concoction directly and therefore will be absorbed directly. Otherwise the shoes or socks could be influenced to acheive the same goal.