A physicist, Simon Jones was working on contacting other dimensions when he came into contact with Trigon. Trigon gave Jones powerful psychic abilities, and instructed him that he should use them to destroy the earth.
Psimon was created by Marv Wolfman and George Pérez. He made his first appearance in The New Teen Titans #3.
The Bronze Age introduced the apparently current iteration of Psimon.
His origin and story appears to have been relatively unchanged following the Crisis, and remained so throughout several universe changes.
The character was apparently significantly altered for the New 52. Portrayed as a teenager or young adult, Psimon apparently possessed inborn psychic talents, the extent and nature of which are unknown. He had the ability to kill people using only his mind, though he appeared to need to use the phrase "drop dead" to focus these powers. The next time a character identifying himself as Psimon appeared, he resembled the traditional Psimon. It is unclear what relation these two characters have to each other, if any.
Major Story Arcs
The Fearsome Five
Seeking to obey Trigon, Psimon joins up with Dr Light's Fearsome Five, becoming a founding member of the group. During their first outing as a team he usurps Dr Light's leadership of the group and attempts to psychically influence the Titans to kill the Justice League. This plan fails. He and his team engage in minor crimes for some time, until Trigon banishes him to an alternate dimension as punishment for his failure to destroy the world. His team is able to pull him back into their dimension using technology in Titans Tower, but are captured and imprisoned in the process. They are broken out, and Psimon leads the team in another mission that ultimately ends in imprisonment
Crisis on Infinite Earths
During the Crisis, Psimon is amongst the heroes and villains summoned to aid the Monitor. He is rescued from a shadow demon attack by Brainiac and Lex Luthor, and recruited into their effort to take over several of the remaining Earths. He doesn't trust them, however, and turns on the pair when he learns that they intend to rule the worlds themselves. He destroys Brainiac and attacks Lex Luthor, but has his brain destroyed by Brainiac, who had faked his death.
By unknown means, Psimon is restored to life, and spends some time in distant star systems, brutally attacking the planets Kallas and Talyn before returning to Earth. There he attacks several of his former allies who he sees as having betrayed him, shattering Shimmer, stabbing Mammoth through the head, and shrinking Gizmo to subatomic size. Following an attack on the Titans he is captured and imprisoned by the Darkstars in the Slab. He later orchestrates a mass escape from the Slab.
Five by Five
Psimon joins Doctor Sivana and the newly reformed Fearsome Five in a plot to short sell LexCorp stock by stealing account information and killing people in LexCorp buildings. When he and the other members demand Sivana allow them to assault a LexCorp nuclear facility, Sivana refuses, killing Gizmo and severing ties with the remaining group. They attempt to take the facility anyways, and are stopped by the Outsiders. Psimon is able to evade capture.
Psimon is the leader of the surviving members of the Fearsome Five, and together with them joins up with the Secret Society of Super Villains. He and the rest of the team are sent after, and manage to capture, Pariah.
Psimon is among the villains transported to the planet Salvation. There, he attempts to lead the villains, claiming that it is impossible for them to escape and the best option is for them to settle into life on the planet and create their own utopian society. Several villains disagree with this plan, particularly the Joker, who bashes Psimons head in with a rock, killing him.
Light and Dark
Psimon appears in New York, killing an entire coffee shop full of people when one of them is rude to him. Later he encounters Trigon, who does something to his powers. Caught up in the ensuing chaos when the Teen Titans arrive, Psimon apparently kills a group of soldiers who arrive to combat Trigon, and is attacked by a possessed Beast Boy. He attempts to use his powers against Beast Boy, but they cancel each other out, and Psimon is rendered unconscious. He awakens, but is again knocked unconscious by Impulse after trying to use his powers to kill Solstice when she criticizes his murder of the soldiers. Still unconscious, he is taken into custody by a clandestine pandimensional think tank.
Psimon is invited to join the Crime Syndicate's Secret Society of Super Villains. He does so, and he and other members of the Fearsome Five are sent after the Rogues. He is trapped in a mirror alongside several other villains and shattered.
Teen Titans Go!
The version of Psimon designed for the animated television series Teen Titans makes an appearance in issue #43 as the leader of a new iteration of the Fearsome Five
In an alternate timeline, Psimon is in prison, with Atomic Skull as a cellmate.
Psimon is depicted as a LuthorCorp experiment, Part of their attempt to create a super soldier in Project ARES. He goes on a rampage through Metropolis, and is imprisoned in Stryker's by Superman and Impulse.
Powers and Abilities
Psimon has immense telepathic and telekinetic abilities. He often uses his abilities to manipulate others and instil great fear in them. He can read minds, cast illusions into them, and possess them. He can also move objects, including large objects and those outside of his range of sight. He can levitate himself, allowing flight.
Psimon appears as a member of the Brotherhood of Evil in two episodes of this series, "Calling All Titans" and "Titans Together." He is part of the team that subdues Raven, and is ultimately frozen alongside many other villains. He does not speak in his appearances.
Psimon appears in five episodes as a member of The Light, making his first appearance in the episode "Bereft." He uses his powers to mentally manipulate the members of the team, and is rendered catatonic for much of the series following a confrontation with Miss Martian. He is later called upon to help recover Aqualad's mind, but prevented from doing so by Artemis. He is voiced by Alan Tudyk.
Young Justice: Legacy
Psimon appears as a boss in this game, based on the television series of the same name. In his appearance he is s puppet of the Riddler. He is voiced by Jeff Bennett.
DC Universe Online
Psimon appears alongside the other members of the Fearsome Five as a part of the "Sons of Trigon" downloadable content. He is voiced by Timmy Morgan.