“All unicorns build doomsday devices!” Those five words were words that Twilight Sparkle never expected to hear next to each other and in that specific order in a sentence.

King Sombra has returned, and upon discovering that Twilight Sparkle has not even considered building a doomsday device, has given her an ultimatum: Either she builds a device that has the sole purpose of destroying the world, or he starts defacing her books.

The clock is ticking: Will Twilight be able to get in touch with her inner mad science and save her imperiled reading material? More importantly, is she really destined to bring about the end of the world? Are unicorns really nothing more than a cosmic reset button, poised to bring a halt to all existence at a moment's notice even in the face of past evidence suggesting that they're not very good at it? Will Twilight succeed where all others have presumably failed? Does she even want to?

Join in as we follow the journey to answer the question on minds the world over: “Anypony for Doomsday?”

Searching for any records King Sombra may have left behind, Twilight learned of the shadowy king's tragic past. However, she also discovered his horn, in which his mind and remaining power were contained. Determined to learn how to use his Dark Magic for Good, Twilight brought Sombra back to Ponyville with her. After all, what could he possibly do as a horn? ...Or will he stay that way?

Edited by Darth Vendar and Myrkur
Inspired by Issue #1 of FIENDship is Magic
Gore tag just to be safe.

Edit 06/15/23: Now in the top 2K stories on the site, by rating! Thank you all!