A previously established character joins the evil side, and works as one of the Mooks. They may or may not be acting on their own free will, but one thing is for sure: they have officially changed sides. They are not just Dressing as the Enemy, or forced to disguise as one. They are one of them. At best, they are the Reverse Moles who have decided to keep up the charade a bit longer. At worst, however...
Uncommonly for an Evil Costume Switch, if any, their new outfit tends to be less distinctive to reflect their new position as a low-ranking member. They may be provided with a uniform and disallowed to customize it any further than Uniformity Exception. They may even be masked into Faceless Goons (handy for a later Dramatic Unmask).
- See also FaceHeel Turn and FaceMonster Turn for possible reasons for their voluntary and forced change of mind, respectively.
- MookFace Turn is the opposite of this trope.
- May subvert What Measure Is a Mook? if they are treated better than the other mooks.
- Nineteen Eighty-Four: The protagonist ends up being just another would-be rebel who's brainwashed into a model citizen and quietly terminated.
- Star Wars: Return of the Jedi: One of Jabba the Hutt's guards is really Lando Calrisian in a face-concealing helmet. With how long he stays in-character as a guard (several days at least), he apparently went undercover by legitimately joining Jabba's organization, rather than just stealing a uniform.
- Played for Laughs in Deadpool (2016) during the final battle, when Deadpool discovers that one of the mooks he's fighting is his buddy Bob (a Lawyer-Friendly Cameo of Bob, Agent Of HYDRA). Deadpool proceeds to knock him out then ask him how his kids are doing.
- Yu-Gi-Oh!: Dartz Summons four Mirror Knight Tokens of different heights. Later their helmets shatter and fall into the ground: they are in truth the souls of Yugi's friends, who have been turned into these forms.
- The Legend of Zelda: Ocarina of Time: Nabooru is captured in the Spirit Temple. Seven years later, Link encounters a strange orange-hued Iron Knuckle there. After defeating it, the plates of armor fall off the Iron Knuckle, revealing Nabooru as the one inside. Nabooru had been Brainwashed and Crazy, and thus forced to attack Link.
- Naruto: In the anime adaptation of Shikamaru Hiden: A Cloud Drifting in Silent Darkness, Shikamaru is captured and separated from the Huge Guy, Tiny Girl duo. Guarded by two hooded figures (one small, one big), he is brought to the villain. Shikamaru asks for the duo, which are revealed to be the guards, having been Brainwashed by the villain.
- Shiren the Wanderer 3: The Sleeping Princess of Karakuri Mansion: One of the Elite Four transforms Shiren into a mindless Mascot Mook, forcing his allies to go look for him through Catfish's Nest.
- Doubutsu Sentai Zyuohger: Quval uses a syringe device to merge Zyuoh Tiger with one of his Moebas. In this form, she becomes Quval's loyal servant who will attack even her good friend Tusk. After taking several hits from her, Tusk is able to snap her out of Quval's control and restore her to normal.
- Kamen Rider Zero-One: The hacked HumaGear can corrupt other HumaGear and transform them into Trilobite Magia by piercing them with tendrils.