Goofer Dust

From Wikipedia:

Goofer dust is a traditional practice of the African American tradition of hoodoo from the South Eastern Region of the United States of America. It can be used generically to refer to any powder used to cast a spell, especially if harmful in nature, but specifically refers to a concoction of natural ingredients that can be used to cause harm, trouble or even kill an enemy. Some historical sources, such as some of the interviews conducted by Harry M. Hyatt indicate goofer dust can be synonymous with graveyard dirt. It is sometimes used in love spells of a coercive nature, the severity of which range from the goofer dust being used to provoke helpful spirits to coax the target into love, to the more extreme "love me or die" spells. Rarely, it has been used in gambling spells.

     In practice, it was often used to create illness in victims, such as swelling of the legs or blindness. Recipes for making it vary, but primarily include graveyard dirt and snakeskin. Other ingredients may include ash, powdered sulfur, salt, powdered bones, powdered insect chitin, dried manure, herbs, spices and "anvil dust" — the fine black iron detritus found around a blacksmith's anvil. The result usually varies in color from "a fine yellowish-grey" to deep "black dust" depending on the formula, and it may be mixed with local dirt to conceal its deployment. 

     The word goofer comes from the Kikongo word "kufwa," which means "to die." Among older hoodoo practitioners, this derivation is very clear, because "goofer" is not only an used as an adjective modifying "dust" but also a verb ("He goofered that man") and a noun ("She put a goofer on him"). As late as the 1930s, goofering was a regional synonym for voodooing, and in North Carolina at least, the meaning of the term was broadened beyond spells of damage, illness, and death to include love spells cast with dominating intent. 

     A euphemistic word for goofering is "poisoning," which in this context does not refer to a physical poison but to a physical agent that, through magical means, brings about an "unnatural illness" or the death of the victim. Even more euphemistic is the special use of the verb "hurt," which is often defined as "to poison," with the tacit understanding that "to poison" really means "to goofer." The more general verbs "fix" (meaning to prepare a spell) and "trick" (meaning to cast a spell) are also applied to goofering.