A Howler is a blood-red letter sent to signify extreme anger or to convey a message very loudly and publicly. Upon opening it, the sender's voice, which has been magically magnified to a deafening volume, will bellow a message at the recipient and then self-destruct. If it is not opened or there is a delay in opening it, the letter will start smouldering, explode violently, and shout the message out even louder than normal.