" Murphy,” I hissed. “Are you absolutely sure about this hair? That it belongs to Kravos?” If it didn’t, the doll wouldn’t do diddly to the sorcerer, unless I managed to throw it into his eye.
“We’re reasonably sure,” she whispered, “yes.”
“Reasonably sure. Great.” But I knelt down, and marked out the circle around me, then another around the Ken doll, and wrought my spell. "

― Jim Butcher , Grave Peril (The Dresden Files, #3)