noun
magic bullet
A bullet with magical properties, often in fantasy or fiction. Can also be used metaphorically for a miraculous solution.
その魔弾はどんな鎧も貫くと言われている。
That magic bullet is said to pierce any armor.
彼は問題を一発で解決する魔弾のようなアイデアを探している。
He is looking for a magic-bullet idea that solves the problem in one shot.
Compound of 魔 (ma, 'magic, demon') and 弾 (dan, 'bullet'). The exact origin is uncertain, but it likely arose as a direct translation of the English 'magic bullet' in fantasy contexts.