待我长发及腰恐怕已成人妖
[dài wŏ zhăng fā jí yāo kŏng pà yĭ chéng rén yāo]
An exaggerated statement saying “By the time my hair reaches my waist, I'll probably already be a fairy-tale monster.” Used self-deprecatingly to joke about changes over a long period, particularly appearance changes leading to unexpected or undesirable outcomes.