Marc Spector (Earth-8150)

Marc Spector was a third-rate criminal and racketeer who experimented with himself at the Blackgate Penitentiary, turning him into a Metahuman with extrasensory perception, enabling him to control others, invading other's dreams, and also making them nightmares. He named himself Sleepwalker and attempted to destroy the Justice League, almost succeeding more than once and thus becoming one of their most dangerous enemies.