Used in old voodoo practice, it is a mixture of natural ingredients that can be used to cause harm, trouble or even kill. The word goofer comes from the Kikongo word "kufwa" which means "to die". As late as the 1930s, "goofering" was a regional synonym for voodooing, and the meaning of the term was broadened beyond spells of damage, illness and death to include love spells cast with a dominating intent.
Often used synonymously for graveyard dirt, which is usually the primary ingredient along with snakeskin and sulfur. Goofer dust is used to keep hellhounds at bay, as they won't cross it. However, it has no effects on at least some demons, as Lilith was able to open a door and break its barrier with no effort.
What, you boys think you know somethin' about somethin' but not Goofer dust? ... Hoodoo. My grandma taught me. Keeps out demons.