Image imported from derpibooru 
Original Description:
 
The Clock with Three Faces  
Colgate is Ponyville’s premier dentist. Also its only dentist. Funny how nopony can remember ever visiting her for a checkup. When a past that she can’t even remember catches up with her, she is sent along with her friends back along her own timestream– or somepony’s timestream, anyway. Who is Romana? Who is Minuette? What do they have to do with the recurring nightmare that Colgate can never remember upon waking? And what lies at the end of this trip down memory lane?
 
Original version