And it’s time once again for MLP Headcanons With Aerin! YAAAAY!
 
Okay, so you know how Luna is the guardian of dreams or something like that? Well, I figure that somebody down the line waaay back in the age before Luna had her little fit of jealousy noticed that heeeey the Princess of the Moon is like constantly in the background of all of my nightmares why is that and started talking about it and then other ponies were like heeeeeey she’s in all of mine too and so everybody drew the correlation between Luna and their nightmares and so they started calling her ‘Princess Nightmare Moon’ behind her back
 
and then she found out
 
and that was the final straw
 
that was the final push for her to become Nightmare Moon
 
she realized that all the ponies regarded her and her night with fear and decided what the hey, let’s give them to give them something to really be afraid of
 
I dunno it’s just my new Luna headcanon (◡‿◡✿)