Please note that this is the Narutopedia's article on the technique used by the Kedōin Clan. If you are looking for the article on the technique used by Orochimaru then you should head to Vanishing Facial Copy Technique.
The user looks at a target to copy their appearance. A flawless Transformation Technique, the copied person's allies would not tell the difference and ninken would not smell a different scent. Though the user copies the person's face and body, they can't use their techniques or unique abilities and they are also very weak to attack. In order to copy an appearance, the user needs to wear a special mask and stay close to the target for a long time. When the technique starts, the user's eyes start to glow. The transformation lasts for only a few days. This technique is unique to the Kedōin clan.