AKA The Snailmancer and the Long Winter's Bridge
AKA Princess Celestia and the Snailmancer
AKA The Crossing of the Bridge in Long Winter
(Et cetera, stories like these often have alternative titles!)

Original Snailmancer fairy tale here: http://haretrinity.deviantart.com/art/MLP-comic-Tales-of-the-Snailmancer-1-266848870

People liked the fairy tale part of the comic a lot, so I did another. Enjoy!