Practicing spells for decorating her house one night, the next morning Twilight Sparkle was surprised at the results... All these inflatable reindeer in her room! How perplexing, there were hints that reminded her of something about them, but no, they were just simple decorations.

Here we have the mane 5, sans Twilight, transformed into squeaky identical rubbery reindeer! There is some TG involved, due to the horns and bulges, as well as reality transformation, because of the power of Twilight's magic. Poor Twilight has no idea of the fate that has befallen her ex-friends, now plastic reindeer, perfect to decorate her house over the holidays!

Rarity and Applejack were the first to be transformed, they're standing tall, taut with air as they squeak and wiggle slightly. Rainbow Dash and Pinkie are feeling the last few moments of their former lives slipping away as they twitch and fondle themselves, whilst Fluttershy has deflated, crumpling flat under the other reindeer's hooves.

A bemused Twilight, not recognizing the toys, was confused as she came down the next morning, hope the reindeer enjoy their new lives! Their painted on grins should help with that~
Inspired a story found here (warning: identity death, permanence and reality rewrite).
As well as a sequel pic (which doesn't take in account the aforementioned story and where things get a better end): >>3515282