" Hardly worth the effort, really,” he muttered. “It’s a homunculus lock. Only opens when a predefined set of factors is present. Could be it only opens when a redheaded lass sings the national anthem of Atlantis at three o’clock on a Thursday. Or when the light of the setting sun is reflected from a cracked mirror onto a goat’s eye. Or when Mr. Grey hawks a bogey onto a purple newt. I’ve seen some good homunculus factors in my time, yar. "

― G. Norman Lippert , James Potter and the Hall of Elders' Crossing (James Potter, #1)