Kpop song teasers that changed your life

I know there are many iconic k pop songs but what are your fav song teasers which shook you, like you had to sit down for a minute and actually prepare yourself to hear the full song in two days or the ones which brings back the nostalgia of your fav era cuz this is where it all started. For me, it's spring day (HAPPY BDAY QUEEN) that teaser is beautiful, it struck a chord in my heart, gets me emotional everytime.