“Sorry your Majesty, but this time you’ve gone too far.”
 
Once upon a time in Doctor Who there was a planet called Mondas. Located on the opposite side of Earth’s sun.  
In Ask Mister Clever there is an alternate version of Mondas, inhabited by ponies.  
Unlike its sister planet, this world had only one alicorn who controlled the planet’s rotation; King Argentum.  
But he was a pompous asshole who wasn’t particularly popular.  
One day he discovers there’s a planet on the other side of the sun, and decides to investigate.  
There he made a terrible discovery… Not only was he NOT the only alicorn in existence, on this other planet lived a white alicorn who also considered herself the master of HIS sun. But aside from this he and the other alicorn had nothing in common.  
She was uninterested in power, and would rather just be friends with her subjects.  
Self-centered as he was Argentum hated the idea of sharing a sun with this silly Princess.
 
So he flung the planet out of orbit.
 
This didn’t exactly help on his popularity.
 
For those not that familiar with Doctor Who Mondas would eventually become the birthplace of the Cybermen.  
Who-canon doesn’t have a very good explanation as to how it suddenly got thrown out of orbit, so for the magic pony version I decided to invent a story of a jealous alicorn.  
And that’s how Argentum was born… and as a side-effect, his three disgruntled guards.