This study analyzes how contemporary collectives that grow fast in scale organize their actions. We conducted a qualitative study of the largest contemporary social movement FridaysForFuture. Our findings reveal that the collective was calling others for change, but their own structures and values only become prefigurative over time. In the beginning, FFF set up hierarchical structures by orienting towards past patterns of actions. This was not a rational planned consideration but a quick response to the overwhelming increase in membership. However, as hierarchical structures have naturally emerged, the collective began to fight against the very same structures because they seemed to be unfitting their collective value “basic democracy.” Hence, they turned towards the future to imagine alternative patterns of actions, fighting against the initial hierarchical structure for a flatter heterarchy. Our findings contribute to research on collective action by highlighting the process of becoming prefigurative.