Jervis Tetch, also known as the Mad Hatter, is a DC Comics supervillain and a member of Batman's rogues gallery. Obsessed with Lewis Caroll's Alice in Wonderland, Tetch modelled himself after one of the book's characters and made a career of committing crimes themed around the story. His talents included hypnotism and mind control; he often used devices designed to warp and manipulate human minds, turning ordinary people into his brainwashed puppets.
Batman: Bad Blood[]
In the DC animated movie Batman: Bad Blood, Tetch (voiced by Robin Atkin Downes) is one of several villains hired by Talia al Ghul to help her in her schemes to brainwash Batman and take over the world. With his talent for manipulating and molding human minds, Tetch was tasked with reprogramming Batman into becoming Talia's loyal minion. For three weeks, Bruce Wayne was a prisoner of the League of Assassins and during this time, Tetch subjected Wayne to a series of brainwashing procedures.
While Wayne would later be rescued by Nightwing, Batwoman and Batwing, this was also part of Talia's plot. A week after his ordeal, Bruce attended a Wayne Enterprises tech summit to showcase his company's latest innovation in telecommunications. Tetch and Calculator hack into the control systems for the new devices Wayne is demonstrating and Tetch interfaces with the system via his hat. Taking control of the network, Tetch begins broadcasting a signal through the devices, brainwashing all of the dignitaries and diplomats attending the summit.
While Tetch is busy brainwashing the attendees, Alfred Pennyworth enters the room where he fights with Calculator. Calculator is kicked into an electrical fuse box and electrocuted, and the power surge causes the system to overload and feedback on Tetch, causing Tetch's head to explode.