A badgermole horn is a musical instrument invented by, and associated with, the Yonggan people of the Earth Kingdom. Its original purpose is to communicate with trained badgermoles, who are instinctively responsive to music. The badgermole horn is a capped double reed instrument similar to a crumhorn, with a long spike that is planted in the ground to facilitate the transmission of vibrations into the earth for communication with subterranean badgermoles. A Nara Badgermole Horn represents a further refinement in which the spike is attached to a thin section of wood inside the bore of the instrument, producing a better impedance match between the oscillating air column and the ground. The instrument is usually made of hardwood, but stone and metal instruments are sometimes seen as well, the former constructed with earthbending.
The traditional working badgermole horn is a bass instrument with a range of about C2–D3, but higher-pitched instruments are made for musical use; the badgermole horn has been thoroughly incorporated into the secular and religious musical traditions of the Northern Earth Kingdom quite apart from its use in directing trained badgermoles.