Front page of the Half-Blood Prince's book

A spell from the Half-Blood Prince's book that fills the ears of anyone nearby with an unidentifiable buzzing


Muffliato fact file


Purpose

To allow secret conversations in public places

The effect it has on the recipient

Causes those around to hear only a buzzing noise

Famous moment a wizard or witch uses it

Used often by Harry, Ron and Hermione while hunting Horcruxes