Having remembered everything, Flowey wanted to insult the Player, but the Player frightened him, saying: “Don’t dare to talk to me like that, otherwise I will tear out and recount all your petals.” Grabbing the stem of Flowey, he remembered everything that happened in all time lines.
Having completed all the endings, they already knew perfectly well that, in fact, this flower is evil itself. Like everyone else, the Player meets Flowey, who, as always, wanted to appear to the stranger as a “friend”, so that he would later nastily stab him in the back. It all starts with the fact that our hero appears on the flowers, as the children did. 5.2 The Power to change the plot of Worldlines(AU’s).5.1 The Power to travel through Worldlines(AU’s).5 Abilities (~Canon~) All sources of info comes from here.