Please see title for details. And no, I'm not going to wuss out by making it about a musical horn or something, this is Twilight's actual magical horn. Also don't worry, it's a lot more light-hearted than it sounds. Kinda.
Spike the dog is about to enter a rare stage in his life, thanks to a strange object, his dog form had suffer a brutal change, a significant change worthy of any human.
(Sequel to "Dragon of Steel", familiarity with the former is strongly recommended. Based on "Superman II", both the theatrical version and the Donner cut.) Spike, as Super Dragon, is pitted against Garble and two other dragons.
Discord decides to retire and a strange being not only took his place as the new God of Chaos, but choose Spike to be it's new protégé. The age of Discord has ended. Thus rises the dawn of Maelstrom.
In an alternative universe, Spike's transformation went a little... differently. One where there were less princesses and singing, and a big heaping dollop of sarcasm.
When Twilight gets an advance preview of what she'll look like a few years after ascending the throne, she is not impressed. Can a certain special (soon to be not so) little guy help her see that the future might not all be that bad, after all?
Spike has been volunteering time to entertain the fillies and colts at the local hospital. Everything changes, however, when his kind actions are noticed by a mare with much less fortunate circumstances.
Tomorrow is take you child to work day. But seeing at Spike Drake is the secret son of Princess Celestia, he can't really enjoy such a day with his mother. So how about the next best thing; A night out with his aunt.
Twilight wakes up one morning, and she can't say a word. Neither, for that matter, can anypony else. In fact, all the sound in Ponyville seems to have gone overnight. Is there a logical explanation for this? Probably not. An illogical one? Maybe...
Twilight wakes up one morning as a dog. Also, Spike is now a fish. Pretty self-explanatory, really. And believe it or not, the day is about to get even stranger.
After an unfortunate accident, a bedbound Spike is enjoying the experience of being pampered so much it's almost like he doesn't want to get better. Perhaps what he needs is a little persuasion, curtesy of an unlikely source...