In Equestria's early history, years before Luna had become a princess like her sister, ever before she gotten her cutie mark, she was once plagued with nightmares. She wanted to sleep without these monsters and demons to haunt her. Help does come in a blue box, from a stallion who calls himself "Doctor", with is assistance, and a pony whom everyone thought was Luna's imaginary friend.
Author's note: I do not own any rights to "Doctor Whooves and Assistant" by the fantastic YouTube radio drama series by Ponies with Pockets Productions aka PrierceSmoulder. This story is a tribute to their series that get's better and better with every video.
Also, a huge thank you to SecretBrony01 for editing this.