Psycho-Man is a villain in the Marvel universe. He lives in the Negative Zone and has the power to control the emotions and mental states of his enemies.
Psycho-Man is a mad scientist, the leader of a technocracy that governed a system of worlds within a Microverse. Facing overpopulation, he determined that it would be easier to cross other dimensions than to travel to other systems. Deciding that Earth would be an ideal target due to its inhabitants vulnerabilities to his unique weaponry, he used scientific means to enter the normal-sized universe, though he was only able to achieve microscopic size in this world and has to resort to a human-sized, armored exoskeleton to interact with anything not on a microscopic scale.
Using a portable device capable of influencing people's emotions, Psycho-Man used a number of human subjects to build a larger-scale version of the machine, one capable of covering the world with its emotion-influencing rays. This effort was thwarted by the Human Torch and The Thing, several members of the Inhumans, and the Black Panther, and Psycho-Man was forced to retreat back to the Microverse. He was subsequently followed by the Human Torch, the Thing, and Mister Fantastic, who were forced to let him go in order to deal with a greater threat back in their own dimension. Psycho-Man later faced the Fantastic Four again, as well as a group called the Micronauts who were native to his home dimension, by which time he claimed to be in exile from his homeworld.
Infuriated by his defeat at the hands of the Fantastic Four, Psycho Man became increasingly obsessed in finding the Uni-Power. He planned to steal the Uni-Power, become Captain Universe and then travel to Earth where he would exact his revenge. He scoured the Universe and captured hundreds of people who had been Captain Universe, however by the time he got to them the Uni-Power had moved on. It ended however when the Psycho-Man captured Spider-Man, who broke free and led a revolt against Psycho-Man with the other previous Captain Universe hosts and eventually defeated the villain, leading him to be tossed from his own ship while his former captives took possession of it.
Eventually he returned to Earth and had given up on finding Captain Universe, so he used an android known as H. M. Unger (also known as the Hate-Monger) instead; to stimulate hatred among the population of New York City through demagoguery and chemically-treated pamphlets. The Hate-Monger also succeeded in turning the Invisible Woman into the hateful warrior Malice, sending her to destroy her teammates. After her husband, Mister Fantastic, succeeded in breaking the Invisible Woman free of her conditioning, the Fantastic Four pursued the Psycho-Man back to his home dimension once more, where they found they had conquered a kingdom ruled by their friend Queen Pearla. There the Invisible Woman confronted Psycho-Man and used his own emotion-control device on him by subjecting him to all three emotions simultaneously at maximum intensity, collapsing his nervous system.
Psycho-Man returned later, to confront Spider-Man, Shadowcat, Douglock and others. Spider-man's experience helped the group escape his influence.
He also became involved with Captain Marvel and Marvel's evil, alternate-universe-future double Fredd.