Tantabi

Incarnations of a powerful magic user's potent feelings, born and nourished by their regrets and anguish. Magical manifestations so strong, they gain a mind of their own, influenced by their original's darkest desires and most primal of instincts. Their ultimate goal is to fulfill their user's most heartfelt wish, unhindered by mental constructs like morality. Thankfully, or perhaps unfortunately, they are caged within the user's mind upon creation, and they can begin to influence and even overtake the user over time. Although cases of this happening have been incredibly rare since the magic needed to create one is far beyond the capabilities of normal creatures and ponies, there have been a few recorded cases of it in the distant past.

Ancient texts speak of a chilling theoretical possibility. From the very words of a pony who had been inflicted with one, translated to the best of my ability: "The magic mist had grown too strong. It rent the heavens of my dreams and nearly tore into the waking world. The damage it would have unleashed would have been catastrophic, had I not stopped it."

The scroll I took those words from is old, and unfortunately, the answer to stopping a Tantabus has been weathered by Father Time into illegibility, but all my research on them has given me one undeniable answer: I pray Equestria will never find itself facing even just one of them. The world would not have a hero big enough to save it then.

Cover Art was drawn for this story by DamayantiArts on Deviant Art. If you like her work, let her know!

Additional tags for involved characters: Luna and Celestia.