Bead of Thorned Magic

Wondrous item, common

These odd objects are sometimes found looking like cysts in corpses. When a spellcaster suffers a Woeful mishap, a bead of thorned magic absorbs the outflow of magical energy that would normally alert undead, preventing them from becoming automatically aware of, and drawn toward, the source. Doing so causes the bead to lose its power and crumble into white powder.