Akumatized villains

Akumatized villains, also called evilized villains, are people transformed into supervillains by Hawk Moth and his akumas.

Transformation
Whenever a person is having strong negative emotions, such as anger, jealousy, and sadness, Hawk Moth senses it and charges a butterfly with power to form an akuma. The akuma flies off from Hawk Moth's lair to where the person is, and it possesses an important object that belongs to the person. Immediately, Hawk Moth telepathically links up to the person in order to communicate, using his butterfly-shaped light mask that goes around his and the person's eyes. He then explains to the person that he'll give them the ability to do want they want if, in turn, the person is supposed to retrieve the Ladybug Miraculous and Cat Miraculous from Ladybug and Cat Noir, respectively. Once the person agrees, a black and purple smoke appears from the possessed object and surrounds the person. Once it vanishes, the person has become a supervillain. If Hawk Moth needs to telepathically talk with them again, his light mask reappears on both of them.

Defeat
In order to defeat a villain and release the akuma, their special object that the akuma infects needs to be destroyed. After the object is destroyed, Ladybug uses her yo-yo to capture the akuma and revert it back into a normal butterfly. When Ladybug's power fixes everything that has been damaged since the supervillain was created, the supervillain is changed back into a person, either with the ladybug power or the smoke, without memory of what they did as a supervillain.

Abilities
An akumatized villain usually has an appearance and abilities that relate to their infected object, occupation, and/or interests. For example, because of Xavier Ramier's love of pigeons and his object being a pigeon call, he becomes Mr. Pigeon, a villain with a suit based off of pigeons and the ability to command pigeons. In whatever way they're changed, an akumatized villain usually have enhanced abilities and skills. A lot of the time, their objects end up becoming their weapons, such as the Bubbler's bubble wand and Lady Wifi's cellphone. Besides from their peculiar powers, supervillains seem to have enhanced strength and fighting skills (like Lady Wifi who manages to beat Cat Noir when both disarmed or the Mime who is able to hold the Eiffel Tower).

Every villain, after being corrupted, remembers the cause of their distress and the person who caused it, so they usually try to get revenge. Additionally, some villains, namely Copycat, the Evillustrator, and Horrificator, remember the people whom they have romantic feelings for (respectively Ladybug, Marinette and Ivan) and still care for them while transformed.

If a supervillain doesn't go and retrieve the Miraculous like they were asked, Hawk Moth can control their bodies for a short period of time in order to stop them from using their powers.

List of akumatized villains
To see each villain's akumatized object, see List of akumatized objects

Trivia

 * Many of the supervillains' face masks, like for Stormy Weather, Lady Wifi, and the Evillustrator, look similar to the shape of a butterfly.
 * In the show so far, none of the people turned into supervillains have become a villain more than once. The closest thing to this happening is in "The Evillustrator" when Nathanaël's fantasy includes Lady Wifi and Stormy Weather.
 * By mid-season, Chloé is directly or indirectly responsible for many people becoming vulnerable to Hawk Moth's akumas and turning into supervillains.
 * Cat Noir and Ladybug usually try to persuade the supervillains to calm down and stop their rampage when they get a chance to do so.