Psimon is a pale bald man. His brain is visible though a clear dome over it, with some strips of skin over the dome. Three red lines are seen on each cheek. He typically wears a grey trenchcoat with a hood. Beneath the coat he wears a black shirt and grey pants.
Psimon worked with the Bialyan government in studying an extraterrestrial sphere that was sent from another world. When the Team arrived to investigate, he blocked the last six months of their memory, slowing down their interference. When Psimon tried to erase Miss Martian's mind again, they engaged in a mental battle. With help from Superboy, Miss Martian was able to defeat Psimon and send him flying.
Psimon later reported to the Light on his failure with the sphere and recapturing Superboy. They revealed that the operation could be considered a success, given that the Light's newest partner has an operational delivery system, one that sent them the extraterrestrial sphere.
Psimon was once again working for the Bialyans, using his mind control abilities to brainwash the president of Qurac, Rumaan Harjavti, into handing his country over to Queen Bee. When confronted by the Team, Psimon telepathically battled Miss Martian, forcing her to reveal her true form and subjecting her to her worse fears and insecurities, all while video-recording her transformation for posterity. Pushed to the edge, M'gann managed to mentally overpower Psimon, rendering him catatonic in the process.
Still comatose and bound to a wheelchair, Psimon was somehow controlled by the Riddler, who used him to spring a trap for Nightwing and his Alpha Squad, while they were tracking down Helena Sandsmark. After luring them to Haly Circus, the Riddler, via Psimon, trapped the Squad in his mind realm, where he created a dark version of each member of Alpha to fight them. Psimon was eventually defeated, releasing Alpha from his psychic grip. He was found behind a curtain, comatose in a wheelchair.
Psimon recovered from his catatonic state, but hypnotized his doctors into believing he was still catatonic and left them tending an empty bed for months.
Psimon led a team of villains, consisting of Mammoth, Shimmer, Icicle Jr. and Devastation, tasked with kidnapping runaways and stray teenagers for the Partner. They used a base in the Bialyan desert as a transportation hub.
After Devastation caught the trespassing Wonder Girl, the base went into lockdown. Inside, Psimon caught another young hero: Batgirl. He knocked her unconscious with a mind blast, and ordered his cohorts to place her in a pod with the other abductees. He waved away Icicle's concerns that she was too high-profile to be held captive; he simply didn't care. He ordered them to prepare a nearby plane for transport of the abductees.
He noticed something was wrong with Shimmer: it was actually his old nemesis Miss Martian. He engaged her in psychic battle, and ordered Icicle to kill her while he kept her busy. He hadn't counted on Bumblebee, who used her stingers to distract him. With a blast to the head at point blank range, she knocked him out.
Bialya February 20, post-10:34UTC+2
Queen Bee checked on the damage in person and debriefed her enforcers.
Black Manta introduced Tigress to Psimon, explaining Psimon would help restore Kaldur's mind. He asked Tigress to stay in Kaldur's quarters as Psimon completed his work. As Psimon mentally prepared himself, Tigress secretly shot a dart at his neck. Psimon became dizzy, then suddenly attacked Tigress. Wondering why Tigress had drugged him, Psimon used his psychic powers to learn she was really Artemis. Before he could do anything else, he passed out.
Tigress made sure Psimon remained in his catatonic state until after the summit between the Light and the Reach took place, where her and Kaldur's deception was revealed.
Psimon recovered and was given a Bialyan diplomatic passport and the immunity that came with it. He didn't need it to enter the United States: he simply mind controlled the TSA and customs. He made sure to smile to the cameras so the Justice League would know. It was part of his plan to take out Miss Martian. By luring her to a classic movie festival where Hello, Megan! actress Sandra Stanyon was attending, she would be weaker. When the Team sprung the trap, he casually confronted Batgirl, cutting her off from the psychic link, and then trapped Superboy, Beast Boy, Sandra and Miss Martian in the latter's mind, where they had to live out an episode of Hello, Megan!.
Psimon finished explaining his plan to Batgirl. Because Miss Martian was trappped by her own insecurities, he didn't need to do anything to keep her there. He brain blasted Batgirl and slipped away. Once recovered, Barbara suspected he would return to Bialya.
When he has a psychic battle, he shoots black mental energy beams with a red aura.
Telepathy: Psimon is adept at using telepathy, even tapping into M'gann's mental telepathy network with her team and erasing their memories. He usually prefaces his telepathy with "Psimon says," followed by a command.
Mind control: Psimon can control the thoughts and actions of others. Psimon was able to control Superboy's mind to put him to sleep and he could force Miss Martian to show him her true form.