Image imported from derpibooru 
Original Description:
 
Spike was Thorax’s very first friend. Meanwhile, Spike felt lost and alone in a pony world, alienated from his fellow dragons. When the two met each other, each finally felt he had a peer to call his friend! Little did Spike know, he had set the world in motion for the changelings to discover the love within themselves – and stop stealing it from others (except for ex-Queen Chrysalis). Spike is no prince – but the crystal ponies adore him as if he were. He would be the logical successor for the Crystal Empire, if something terrible happened to Princess Cadance and her family.
 
One day, Spike and Thorax had another reunion. Both of them visited the Crystal Empire. On this visit, Thorax arrived in his pony form – that young earth pony who called himself “Crystal Hoof”. He’s been taking this form a lot more lately. But why was this? As many fans know, the changelings seem to suffer from PTSD, for all the years that Chrysalis kept them hungry. She fooled them into thinking they needed to steal love – when, in fact, it was sharing love that would satisfy their hunger.
 
Except for Pharynx, the reformed changelings have regressed to a childlike state, seeking the lost innocence they never had. When Thorax takes on his Crystal Hoof form, he feels that he’s been reborn. No longer does he use this form to disguise himself – he genuinely embraces it as part of himself. Sometimes he even goes to school, to be with the friends he should have had when he was a child.
 
Full of love for each other, Spike and Thorax wanted to feel each other’s warmth. Standing together, they exchanged hugs. As they did so, a great burst of energy flowed through the Crystal Heart … becoming bright like a welding arc! Suddenly, Spike and Thorax found themselves growing and growing – until Spike’s foot was about the size of the Crystal Castle!
 
His toes bigger than houses, Spike could hardly believe his newfound power. His heart was filled with love for Thorax. At the same time … he was feeling a desire for destruction. Feeling drunk with childlike affection, Spike and Thorax walked all over the Crystal Empire. They made a bit of a game out of smashing crystal buildings under their feet and hooves. Spike even ate a few of them, for a light snack.
 
Spike loved feeling the buildings crumbling under his feet and between his toes. It was a lot like walking on the beach. The Crystal Empire was now Spike and Thorax’s little sandbox! Thorax felt kind of weird helping to destroy the Crystal Empire – and even weirder that Spike was doing it with him. But Spike reassured him that love would literally keep everyone alive.
 
Finally, Spike and Thorax sat down, next to the Crystal Castle. At Spike’s feet was the statue celebrating his part in saving the Crystal Heart. These were two of the few things that remained intact. Meanwhile, the Crystal Heart continued to shine with the love between Spike and Thorax.
 
During their destructive stroll, Spike and Thorax had stepped on hundreds of crystal ponies. Some of them got stuck under his feet and Thorax’s hooves. But there was no major injury. They were flattened like pancakes, but they didn’t seem to care. They were drunk with affection for their destructive hero, along with his best friend!
 
Spike and Thorax continued to relax, cuddling with each other. Each was happy just because the other was there with him! As Spike wiggled his toes, he continued to feel the remains of buildings crumble between his toes. He felt tiny crystal ponies stuck under his feet, hugging his feet.
 
Spike could literally step all over the crystal ponies – but he would never stop loving them. His size-changing powers come from their affection for him and his affection for others. He would burst into tears at the sight of dead bodies. Although Spike and Thorax had destroyed the Crystal Empire, the crystal ponies didn’t really care.
 
Spike adores the Crystal Heart as his precious jewel – and the statue celebrating him. As long as the crystal ponies get to enjoy those things, their hearts are filled with joy and hope. They still have each other, and the magic of their love – and not much else matters to them! In turn, Spike’s heart is warm from the validation that Cadance’s subjects show him – even if she doesn’t feel quite the same.
 
Cadance could almost cry, feeling that her kingdom was destroyed in one fell swoop by two creatures she thought she could trust. But Starlight and Sunburst assured her that the damage would be reversed by the next episode. When their theory proved correct, Cadance discovered a newfound respect for Spike and Thorax. In the end, a kingdom is not defined by buildings – but the hearts and minds of its subjects!
 
(Disclaimer: I do not ship Spike and Thorax. I see them as brothers, not as lovers. I ship Spike with Gabby and Thorax with Ember.)
 

 
Art by Sparky_the_chu (during an Art Slave session). Edited by me. (This is a work in progress, but I did my own edits to provide something I could post right now.)