Sonido is the high speed movement technique of the Arrancar and Hollows in Tite Kubo's Bleach, the counterpart to the Soul Reapers' Flash Step. Ulquiorra Cifer, the stoic Fourth Espada introduced during the Arrancar arc, became its most associated user thanks to his emotionless, instantaneous appearances in battle. Clips of the effect spread through Bleach AMVs and anime edit communities, where it was isolated as a clean teleport sound for fan videos. It remains popular because the rush is short, distinct, and instantly signals Arrancar level speed to fans.