Joker or Mad Hatter ?
The Mad Hatter is a fictional character, a supervillain in the DC Universe who was an enemy of Batman.
Like other Batman villains, the Mad Hatter has become a darker character over the years. The Mad Hatter is depicted as a scientist who invents and uses technological mind-controlling devices to influence and manipulate the minds of his victims, believing that "the mind is the weakest part of a person". .
http://en.wikipedia.org/wiki/Mad_Hatter_(comics)
Powers and abilities
While the Mad Hatter has no inherent superpowers, he is a brilliant 'neurotechnician' with considerable knowledge on how to dominate and control the human mind, either through hypnosis or direct technological means