A triccheballacche looks like someone took three wooden hammers, stood them upright in a frame and decided that the best way to use them was …making music! The middle hammer stays still, while the two on either side swing inward and strike it, and little metal disks fixed to the wood jingle with every blow.
Played well, the instrument produces a rattling, clacking rhythm that can cut through singing and dancing without needing a single string or a drumskin. Its name, in Neapolitan, is an imitation of the noise it makes, which seems only fair: it is difficult to describe that noise any other way.