These "pipe" nests are built by a little dark brown to black wasp by collecting mud and then building tubes for laying its eggs, one egg per pipe. Spiders and other small bugs are paralyzed and sealed inside the pipes for the larvae to feed on when it hatches. 

In folk magic, these nests are used whole, broken, or powdered in hot foot workings, break-up spells, good luck hands, business/employment drawing blends, money drawing, and many, many more.