I needed to make a poster with Moon Dancer since I role play her a lot. Additionally I had to test the new Nightmare Moon too and since both are Moon-related I put them together.  
I started with this picture and finally had even three posters with a strory.
 
 
Background story:
 
Part 1: >>1656002
 
Part 2:  
As we know every ruler need subjects to command at. That’s also true for our dark mare of the moon. At this night she ordered Moon Dancer to bring her good books for her entertainment.  
Tragicly there is a missmatch between Moon Dancer and the royal pony of the night. Full of anger the mighy started to shout at Moon Dancer.  
>Who do you think am I? “Advanced Astronomy”?. I am the queen of the night and I know every star on the firmament.<  
Moon Dancer wanted to respond with a clear mind but the dark pony just didn’t stopped to use her Royal Canterlot Voice.  
Hours later our pale student was dismissed to leave the room without any words spoken.
 
Part 3: >>1656010
 
 
Credits  
Nightmare Castle by dracagon  
Nightmare Moon by beardeddoomguy  
ENH NMM by syndrom  
Moon Dancer by longsword97  
ENH Moon Dancer by stefano96  
Books from FS cottage by discopears  
MLP:Fim by Hasbro