A team of unstable superhuman misfits, Psionex was formed by Genetech, a bioengineering firm specializing in superhuman genetics research. Genetech's founder, Harmon Furmintz, regarded super-beings with both fascination and envy. A 1930s child prodigy, he was recruited in 1940 as a prospective test subject for the super-soldier serum research that later produced Captain America, but Harmon was dropped from the program due to his hemophilia. A collaborator of Howard Stark (later Iron Man's father) and a teacher of Reed Richards (later the Fantastic Four's founder) in subsequent decades, Furmintz came to feel that humanity was advancing all around him while he remained stagnant. Using funding grants from Daryl Taylor's Taylor Foundation, Furmintz founded Genetech to develop a new race of superhumans.
When a Genetech project accidentally resurrected the cosmic menace Terrax, he was defeated by a young superhero team, the New Warriors (whose leader, Night Thrasher, was secretly Dwayne Taylor, the late Daryl's son and heir). Genetech hired the Mad Thinker to research the Warriors, then used the Thinker's date to experiment on five volunteer test subjects, chosen on the basis of their morphological differences and varied socioeconomic backgrounds. All five had their brains enhanced through biochemical, biomechanical or surgical means, becoming superhuman though their mental health deteriorated. Genetech administrator Walter Rosen was uneasy about the project, but CEO Furmintz rationalized the imperfect result as a necessary transitional phase.
Collectively dubbed Psionex, the five test subjects included Asylum, a former mental patient whose dark, mist-like body (apparently held together by a special mask) induced traumatic visions of "inner truths" or "inner lies"; Coronary, a transparent-bodied former medical student who psionically manipulated others' biometabolic processes; Impulse, a violent street gang member armed with neurotoxin-coated wrist blades and superhuman reflexes; Mathemanic, a genius-level M.I.T. student turned "math telepath" able to alter reality (or perceptions of same) by manipulating numerical values such as distance, time or force; and Pretty Persuasions, and exotic dancer who could stimulate the pleasure centers of others and transform her own erotic impulses into painful-yet-pleasurable energy weapons.
When the Warriors broke into Genetech trying to find out why the Thinker was hired to spy on them, Psionex captured them; the Warriors soon escaped, defeating Psionex and smashing Coronary to bits and chastened Rosen admitted the project had gone somewhat astray. As Genetech's experiments continued, Psionex's powers increased – for instance, Asylum could now generate Darkforce blasts, and a freakishly reassembled Coronary could now reshape his form and alter his density – but their mental stability declined, and they rebelled against their employers. When the Warriors struggled to subdue Psionex, a disillusioned Furmintz decided to take control by becoming a super-being himself; trying to gain the powers of Terrax, he was instead assimilated as the villain's new host body. Most of Psionex fled, but Mathemanic was seriously injured and Impulse was crippled; adding insult to injury, Impulse was arrested for his past crimes.
Psionex split up thereafter: a rampaging Asylum was stopped by the Warriors when Speedball dispersed her mist form; Coronary returned to Genetech seeking treatment for his increasingly monstrous and painful physical condition; a wheelchair-bound Impulse was paroled and tried to stay out of trouble; Mathemanic returned to his M.I.T. studies; and Pretty Persuasions worked in a strip joint. None of them were content in their new lives, so when the unstable Darkforce-wielding mutant Henrique Gallante adopted the mask and alias of Asylum, they reformed Psionex under his leadership (Impulse had healed by then, and his sister Chantal's death in a gang shootout convinced him to come out of retirement). The team became crime-fighting vigilantes and popular celebrities despite the Warriors' disapproval, but their crusade ended after Asylum accidentally killed and innocent child. The Warriors convinced Gallante to turn himself in. A quilt-stricken Mathemanic tried to undo the child's death using his powers, but was ultimately forced to restore reality as it was.
During a period when they were estranged from the Warriors, Night Thrasher and Rage joined a reassembled Psionex (the founders minus Asylum) as the team's new mentors, but they soon gave up on the project and returned to the Warriors. Psionex has mostly kept a low profile since then, but they were recently among the many super-criminals captured and pressed into service by Baron Zemo's Thunderbolts.