Here's a WIP of a commission from Riiefu of the Equestria Girls as the cast of the PlayStation 2 RPG Nuga-Cel. Twilight here is "dressed" as Murasaki in her underwear. The female characters in this game fight with magical costumes which have their own "health" so as the characters take damage their clothes will as well. When a costume is destroyed, the victim is stripped to her underwear, her stats drop low enough so almost anything will one hit kill, and she will lose a turn while she covers herself in embarrassment. The only way for your party to avoid the loss of a turn is to choose to remove your costume before it takes one hit too many which triggers them performing a special move in their underwear. So here we have Twilight magically doffing her clothes in exchange for performing a powerful magic attack.