Black Flash is a signature combat technique from Jujutsu Kaisen, used when cursed energy lands within an extremely precise instant of a physical hit. Yuji Itadori's first use became a standout anime moment and spread through fight edits, shorts and reaction clips because the impact feels both technical and explosive. Fans often use this sound for any perfectly timed strike, not just Jujutsu Kaisen scenes. Its staying power comes from how easily it turns a simple hit into a high-stakes highlight.