In Genshin Impact version 3.4, Hoyoverse added a big event called "Second Blooming," in which players could gain a free skin for 4* Electro unit Lisa. However, all the way back in version 2.0, Genshin Impact already added a hidden achievement of the same name, which can be a little bit easy to miss and forget. Furthermore, the skin event having the same name as the achievement while being way more popular has likely made a lot of players who didn't already have the achievement completely unaware of its existence, with all "second blooming" discussions being about Lisa and her new skin.