verb · to undergo biological metamorphosis, specifically the process of a caterpillar or pupa becoming a butterfly

毛毛虫在茧中静静地等待着蝶变的时刻。

verb · to undergo a dramatic and positive figurative change, such as in urban renewal, industrial reform, or economic development

经过几年的治理，这座污染严重的城市实现了华丽蝶变。