Wand Alarm
From Harry Potter Fanon Wiki
A Wand Alarm is a magical device sold by Weasleys' Wizard Wheezes. The Alarm, introduced in 2009 following a rash of wand thefts at Hogwarts School of Witchcraft and Wizardry, is a small ring that shrinks to fit the diameter of an individual's wand, and causes the wand to scream continuously if touched by anyone other than the owner. Because the product was rushed into production to answer the crisis at Hogwarts, early versions of the Alarm tended to also go off if the wand were dropped, bumped, shaken too hard, or sat upon.
