Saimin: Gakuen ((free))

You're likely referring to Saimin Gakuen (催眠学園), a Japanese adult visual novel and anime series from the early 2000s, known for its hypnosis-based psychological control themes. It stands out in the "hypnosis eroge" genre for its dark, manipulative tone and the way it explores power dynamics in a school setting. The narrative follows a protagonist who gains hypnotic abilities and uses them to control students and teachers, often crossing into disturbing psychological territory. Its notoriety comes from blending explicit content with a more serious, tension-driven atmosphere than many contemporaries. If you're interested, the 2003 anime adaptation (by Studio Jam) captures the core premise, though the visual novel offers more branching story paths. Are you looking for plot analysis, thematic discussion, or its cultural impact in niche media?