The kentungan is a traditional Indonesian signalling instrument made by hollowing out wood or bamboo with a slit that resonates when struck. For generations it has been used in villages to announce gatherings, mark night patrol rounds, warn of danger or theft, and call people together. Different rhythms can carry different meanings within a community. It also appears in cultural performances and pagelaran, which helped recordings of its distinctive knocking spread online as a reusable sound effect for edits needing an authentic alert or traditional atmosphere.