群がる
むらがる · muragaru · JLPT N1 · verb-godan
to swarm
群 — 君 jūn (phonetic) + 羊 sheep (semantic)
群 is a phono-semantic compound. The 羊 (sheep) component gives the meaning — sheep naturally gather in flocks — while 君 (jūn) supplies the sound. From the literal sense of a flock, the meaning broadened to any group, crowd, or cluster of people or things.