It is the main villain of A Wrinkle in Time and its 2018 remake.

A techno-organic being, half-machine and half-eldritch alien being, he keeps the population of the planet Camazotz under his control with mind control that combines mind-controlling implants with his own cosmic powers. The brilliant scientist Dr. Alex (or Jack) Murry accidentally travels to Camazotz via the tesseract, at which point It make Dr. Murry into another of his slaves. Dr. Murry's daughter, Meg, uses the tesseract to rescue her father, but in the process her brother, Charles Wallace, has his mind taken over by It. In the end, Meg performs an act of true love, which destroys It and frees everyone from his control.