For those needing a quick refresher: the dress on the left is the one Rarity made Rainbow wear in order to let the lecherous creep Zephyr Breeze paw at her in “Sparkle’s Seven.” That’s the Wonderbolt bomber jacket, complete with the demeaning ‘Rainbow Crash’ patch, from “Newbie Dash” in the center. On the right is the titular costume from “The Mysterious Mare Do Well” with the zombie-cookie smear from “28 Pranks Later” added on the muzzle.
Note: While I actually really liked “Sparkle’s Seven” outside of the unfortunate implications with the Zephyr scene, those other episodes are just terrible. They’re examples of being disloyal to a friend, the one who’s the most loyal to them, no less.