Horagai, the dragon god conch shell

Since the oldest times, a strange instrument was used in Japan, made from a large conch shell, with bronze (or wooden) mouthpiece at the apex of the shell's spire. The Buddhist monks used this instrument, called horagai in various religious activities. A variety called jinkai ("war shell"), was also used in battles to send signal to the troops.

I encountered this instrument at the Mizudome-no-Mai festival, the Rain-Stopping Dance from the Gonsho-ji Temple. One of the two dragon gods, wrapped in rice straws, was blowing the horagai while carried around the temple...