At a first glance it may seem obvious. What can you write with this prompt besides a fairy tale like story? That's where you think outside the box. Exercise those creative muscles. Once Upon a Time....yeah....when? what? who? where? why?
And here's my outcome:
Well, this time my space management wasn't perfect, I simply run out of space when starting that little fairy tale. My plan is to finish it separately and maybe post a translated version here. What do you think? Would you like to read a little fairy tale?