Great shout Great shout was an arcane evocation spell that produced a tremendous sonic force similar to a " horn of blasting " from the mouth of the caster . Effects . There were at least two distinct versions of this spell . The original , presumably invented by a wizard named Daimos , was dangerous to the caster , requiring some of his or her own vitality in the casting , with possibly fatal results . It also required an item that radiated magic as a material component . A later version was much less taxing , did more damage , had a bigger area of effect , and only needed an arcane focus ( which was not consumed in the casting ) . " Great shout " had two areas of effect , one inside the other . The primary area of devastation was a narrow corridor emanating straight out from the caster . The secondary region of sonic punishment also emanated from the caster in the same direction as the primary but was in the shape of a widening cone that surrounded the primary on both sides . For the earliest version of the spell , the primary area was only 1 ft ( 30 cm ) wide by 8 ft ( 2 . 4 m ) long , while the later version had a 5 ft ( 1 . 5 m ) square cross - section that extended out to the edge of the cone ( a minimum of 65 ft or 20 m ) . The edge of the cone for the earliest version was 90 ft ( 27 m ) away . Daimos ' " great shout " was not discriminating in what it affected . The primary area of sonic force could split boulders , flatten a log cabin , or breach a stoutly held gate . Objects in the path were likely to react as if they had been hit by a missile from a large catapult . Creatures took damage and were stunned for at least one minute and rendered deaf for at least two minutes . Outside the primary area , creatures took less damage but were still stunned and deafened . The later version of this spell was particularly devastating to crystal , metal , or stone objects in the primary path of thunderous vibration . Anyone carrying items made from these materials could try to dodge out of the path of destruction , but if they failed , the items were likely to break or shatter . In the secondary area of effect , creatures were severely damaged , deafened , and possibly stunned for a few seconds . Any fragile or crystalline objects in the secondary area were also subject to breaking or shattering . Creatures carrying them could shield these brittle objects from damage by a successful dodge . A " silence " spell was proof against " great shout . " Components . Only verbal and material components were required to cast the earliest version of " great shout " . It needed an item that radiated magic , even if it was just " Nystul ' s magic aura " , and the item was consumed upon casting . The later version had verbal and somatic components but used an arcane focus of a small horn made from metal or ivory . History . The first known instance of this spell was discovered by Ulthorn of Waterdeep when he acquired the " Spellbook of Daimos " around the mid – 11th century DR . After his death the book disappeared , but " great shout " was subsequently used in Ankhapur on the Lake of Steam and in the outpost of Twostars somewhere on the Golden Way . It was eventually published in " Volo ' s Guide to All Things Magical " shortly after the Time of Troubles and became generally known , but it was uncommon to find it .