Transformers Prime: Unicron the Chaos Bringer is a intended one shot story written by Metroid Prime.
The story is told from the eyes of Unicron and Twilight and general switches from both characters.
The story begins at the seris premire with unicron in space as he heads for the pony homewrold of Arion, intending to eat the planets moon with Nightmare Moon in it. The secne swtiches to Twilight reserching about the history of Nightmare Moon, she then assigns Spike to wirte a letter to Celestia about the impending Doom with Unicron watching from space. The events from episode one happen in order to the near end, Unicron the arrives and sucks up Nightmae Moon and drains her of her life force killing her, the ponies of Equestria watch as Unicron finishes eating the moon and then leaves the planets orbit. Twilight then goes home to Canterlot without ever bonding with th mane six, greatly altering the timeline of the show.
In Chapter 2 Unicron comes and Devestates the Canterlot Wedding by killing Princess Cadence.
In the third and final Chapter Sombra has become a slave to Unicron but turns on him, this cuases Unicron to transform in retaliation and begins to attack Arion, Celestia seeing that the world is doomed tries to save Twilight and Spike by sending them into space in a stasis spell, Twilight is reluctent at first but decides to go, she and Spike leave the planet which is eaten by Unicron, the spell then puts Twilight and Spike into hibernation mode.
10,000,000 years pass and it is reveled that Ario is one of the planets from the begining of time and that Unicron was eventually deafeted by Primus, in present day the sphere brings Twilight and Spike to Earth where they crash in the Nevada desert and are discovered by Optimus Prime
End of Story