Did you know that in Divinity Original Sin 2 it's possible to learn a unique skill that applies Deafness and isn't found in any book in the game?
In Act 4, in the Garden of Linder Kemm, we find a terrarium with a visibly special plant. If we interact with it to break the glass, we'll come into contact with this deafening noise originating from the Lamenting Mandrake!
Once we consume it, we gain the unique ability Deafening Scream, removing magical armor and inflicting Deafness on enemies for two turns!