Stryker sent Jason to Xavier's School for Gifted Youngsters in the hope of curing his mutation, regarding it as a disease. However, the school's headteacher, Professor Charles Xavier had no interest or belief in 'curing' mutants, which angered Stryker. Additionally, Jason grew increasingly angry, resentful, and vindictive towards his parents, torturing them by planting illusions in their brains and ultimately causing his mother to commit suicide by drilling into her own brain in order to "bore the images out". In response, Stryker gave his son a lobotomy to make him more docile (as well as presumably taking him away from Xavier).
Stryker eventually found a way to harvest a fluid from Jason's brain which he used to control mutants such as Nightcrawler, Deathstryke and a captured Cyclops. When a kidnapped Xavier's mind proved too strong for the fluid, Stryker instead tried to use Jason's mental powers to directly manipulate the X-Men founder into using Cerebro II, a reproduction of Cerebro, to kill all mutants.
Magneto, wearing a helmet designed to shield against telepathic attacks, was able to reach Xavier, but then had Jason make Xavier use Cerebro II to kill ordinary humans instead of mutants. Magneto escaped and soon thereafter Storm and Nightcrawler entered Cerebro II and disrupted Jason's illusion, freeing Xavier from Jason's control before any humans or mutants could be killed.
Jason was revealed to be still alive. He confronted Nightcrawler in his mission in Alkali Lake, wanting revenge on him since he let him die. Anyway, Jason's personality split in two, a good side and an evil one, and the good side sacrificed his own life in order to help Nightcrawler destroy the Sentinels.
Powers and Abilities
Telepathic illusions: Jason Stryker was able to create psychic illusions and also exert some control over those affected by his illusions. Jason appeared to have extensive control over his illusion ability in that he was able to deceive and control the extremely powerful telepath Charles Xavier (however, it should be noted that, at the time, Xavier's telepathy was neutralized). By the time of his father's attempted mutant genocide, these illusions were at least facilitated by a gas harvested from Jason's body, although this could have been part of his life support chair. Jason also produced a fluid from his brain that could be used to mentally enslave people.
Jason's strength was likely significantly lower than that of a normal human male thanks to his father's lobotomy effectively paralyzing him for years.
It was possible to break Jason's illusions by adversely affecting his physical comfort, and therefore presumably his concentration. Storm was able to free Xavier by nearly freezing Jason.
Jason's wheelchair was equipped with an apparatus which apparently released a gas that facilitated his psychic illusions.
- Michael Reid McKay portrays Jason Stryker in X2.
- The movie's version of Jason Stryker allegedly appears for some fans to be loosely based (beside the original Jason Stryker, and Mutant 143 of the Church of Humanity for his code-name) on Mastermind (because of his powers) and his appearance on Legion (because of the heterochromia).