Trigger

Trigger (トリガー), also referred as Weak Quirk Improvement Drug, is a type of drug that gives a boost to an individual's Quirk, simultaneously weakening their sense of reason.

Overview
Originally, the Trigger was created to massively enhances the power and potency of weak Quirks. However it was soon used for criminal activities, so it was banned in many countries, including Japan, becoming an illegal product with which gangsters and drug dealers around the world traffic.

The Trigger is produced in different regions of the world, so its quality can vary from one place to another. Those produced in Asia are usually of poor quality and their effects only last a few minutes, while the Trigger produced in America can last an hour or two.

Trigger addicts suffer a side-effect after the use that changes their tongues' color to black.

Generally, the Trigger is injected into the body, but it has been possible to develop a variant that only needs to be ingested to work. Although it's less effective than the other form, it lacks the psychotropic element.

Vigilante - My Hero Academia: Illegals
In Japan, there is a criminal organization known as Villain Factory by the police, which shows a special interest in the effects caused by the Trigger. Its agents carry out numerous experiments with the product, distributing it through the streets between junkies and thugs, turning them into Impromptu Villains. Then, they collect all data to study, as well as blood samples from the consumers.

Later, the mastermind behind the Trigger drug abducts some of these Impromptu Villains that showed particular promise, and turns them into Next-Level Villains, altering and enhancing their bodies to make them able to withstand massive amounts of Trigger. This leaves them drastically and indefinitely altered from the dosages.

My Hero Academia

 * A villain amplifies his Blades, sprouting a great number of very long blades from his body. He is capable of controlling them, sprouting and retracting them, as well as focusing them into one place to reach great destructive power. They become sharp enough to nick Eijiro Kirishima's Hardening.
 * Joi Irinaka of the Shie Hassaikai amplifies his Mimicry, allowing him to affect much larger than the physical area of a refrigerator, his normal limit, and to merge with and manipulate an entire underground facility in preparation for the Heroes' invasion.
 * Rikiya Katsukame of the Shie Hassaikai amplifies his Stamina Absorbing, allowing him to use it without making physical contact with others, absorbing stamina by simply inhaling.

Vigilante - My Hero Academia: Illegals

 * Raputo Tokage amplifies his lizard appearance to a strong Pterodon Physiology Quirk.
 * Moyuru Touchi, who only appeared to have a small flame in place of his hair, is amplified to become a powerful flaming rock golem.
 * Soga Kugizaki amplifies his Spike to a Porcupine Physiology Quirk, that sprouts stronger spikes all over his body.
 * Mario Kugutsu is transformed into a massive four-armed giant.
 * Akira Iwakou, whose Quirk was amplified to a Hardening transformation-type Quirk, with additional Enlargement and Super Strength abilities.
 * Teruo Unagisawa, whose Quirk made him somewhat resemble an eel, was amplified to an Electric Eel Physiology Quirk with a large eel's body and small human limbs. He also had greatly enhanced mobility, being able to bounce off the walls of buildings to launch himself into the air and even keep up with Pop Step's Leap. Unagisawa was later abducted by Kuin Hachisuka and seemingly injected with several doses of Trigger over an extended period of time, which lastingly modifies his body into a large electric eel with slippery skin, but this time with very muscular human limbs. He is able to discharge electricity, but doing so renders him unconscious. It is unknown whether this modification is permanent.
 * Kuin Hachisuka, while not initially a user herself, utilizes her Quirk as a specialized delivery system to infect dozens of Quirk-using citizens in order to effectively test drive trigger's potency while in use. Later she uses it to transform her body, strengthening her and allowing her to use an electric quirk.
 * Ichiro Hotta, a trigger dealer, had his quirk amplified to become a humanoid grasshopper.
 * A civilian from Chapter 5 (Illegals), who was amplified to gain blades on his fingers and shoulders, as well as Muscle Enhancement and Enlargement.
 * A civilian from Chapter 5 (Illegals), who was amplified to release electricity from her eyes.
 * A civilian from Chapter 5 (Illegals), who was amplified to release black fluid from his palms.
 * A civilian from Chapter 5 (Illegals), who was amplified to catch on fire.
 * A civilian from Chapter 5 (Illegals), who was amplified to become very large and round, with dark skin and lighter markings. His body also released streams of water from several points.