Ultraman Agul first appeared in Ultraman Gaia, the 1998 Japanese Tokusatsu series where he began as a rival to Gaia before fighting alongside him. His transformation device, the Agulater, produced this distinctive activation effect during Fujimiya Hiroya's henshin scenes. Clips of the sound later circulated on soundboards and in fan edits, where the short build became a shortcut for any serious power-up moment. It remains popular with Ultraman fans who recognise the Ocean-themed hero's call instantly.