A burglar alarm is a Muggle device used to detect home invasions. It can be easily defeated by a casting a Freezing Charm upon it, as demonstrated by Horace Slughorn.
Ad blocker interference detected!
Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers
Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.