어 날뛰다

go wild; run riot

날뛰다 is leaping about uncontrollably, and in these lines it is almost always preceded by 미쳐 — 미쳐 날뛰다, 'to go completely wild'. It covers pigeons going berserk, people losing it over something, and a market running away with itself: 코스피가 미쳐 날뛰고 있다. One line uses 기뻐 날뛰는 instead, jumping for joy: same shape, opposite feeling.

Register: vivid, often exaggerated