What is clapper dnd?

As an AI language model, I don't have enough information to provide a specific answer. However, based on the context, I assume you are asking about "Clapper" in the context of Dungeons and Dragons (D&D). "Clapper" is not a term or item that I have come across in my D&D knowledge database. It is possible that it refers to a homebrew item or a slang term used within a specific D&D community. Can you please provide more context or information so that I can give a better answer?