Do Princesses Dream of Magic Sheep?.Princess Luna's dreams are inhabited by the Tantabus, a parasitic smoke monster that turns her dreams into nightmares. During a dream where Luna (as Nightmare Moon) battles Twilight and her friends, the Tantabus escapes into the six ponies' dreams. Luna enters each pony's dream to catch the Tantabus before it can grow powerful enough to spread its influence into the waking world. Unfortunately, it infects all of Ponyville when Pinkie Pie dreams of sharing ice cream with the whole town, requiring Luna to merge every pony's dreams into one. Despite the townsfolk's efforts to help contain the Tantabus, it grows in size when Luna blames herself for creating it as self-punishment for her actions as Nightmare Moon. Realizing her guilt is what empowers the Tantabus, Luna is able to stop it by forgiving herself. With the Tantabus gone, Luna is finally able to sleep peacefully.