A hardened prisoner who shares Michael Burnham's transport shuttle in 2256 and joins the attack on her in the mess hall of the USS Discovery, blaming the mutineer for a cousin lost in the war.
Psycho is one of three convicts travelling with Michael Burnham on a prison shuttle in the Discovery episode Context Is for Kings, set in 2256. Like her companions Cold and Stone she is known only by a nickname, and she makes no secret of her contempt for Starfleet's first mutineer.
When the shuttle is rescued by the USS Discovery, the prisoners are taken to the mess hall to eat among the crew. Psycho tells Burnham that a cousin of hers served on the USS Europa, one of the ships destroyed at the Battle of the Binary Stars, and holds her responsible for the death.
The three convicts then set upon Burnham, who beats them off using the Vulcan martial art Suus Mahna before security chief Ellen Landry breaks up the fight.