Winterchilla

A winterchilla is a small rodent-like creature with fuzzy fur, large ears, thin fluff-tipped tails, whiskers, and six limbs. It is featured in the holiday special My Little Pony Best Gift Ever and the Best Gift Ever storybook A Present for Everypony. Its name is a portmanteau of "winter" and "chinchilla".

Biography
Rainbow Dash, assisted by Discord, tracks down a winterchilla to give to Fluttershy as a Hearth's Warming present. Discord describes winterchillas as "small, adorable, fuzzy, and fast". They succeed in catching one, but when the sun goes down, it transforms into a giant, monstrous version of itself called a winterzilla. When the winterzilla goes on a rampage, Fluttershy coerces it to calm down with her Stare. Its name is a portmanteau of "winter" and "-zilla".

The winterzilla is a character in Gameloft's mobile game. Its in-game description states, "Formerly a fluffy, adorable little winterchilla... until the sun set, anyway."