Sometimes silly stories are just that, silly stories to keep silly foals entertained and away from places and things of certain fragility or importance.
So was the story Rarity told the CMC to keep them off from her basement, and Scootaloo was up to prove once and for all she was right about it, there was no such a thing as a monster downstairs.

This one shot is situated around season 6.

Thanks to dirty bit for pointing out the typo on the description.