Shadow Pony Real or Fake & Diaries Dos or Don'ts

Hello readers, today was quite an interesting episode about adveturing int the Castel of the Pony Sisters. Twilight saying that the six friends should keep a diary could be a great idea, but I am not so sure of it. Also in teh end of the episode you find out there is such thing as a Shadow Pony, so I guess that is now a new question that has to be answered by show! Leave a comment to tell if you think the Shadow Pony is real or fake and if the diary idea was a do or a don't. Also what do you think is in that case and where in Equestria could they be?