Ray Bradbury's The Veldt Review

The Veldt is a science fiction short-story about a wealthy futuristic couple, the Hadleys, who have spoiled their two children with all the technological marvels that money can buy. Among these extravagances is "The Nursery," a holographic room which displays whatever the user wants it to, complete with realistic sounds and smells. The children have become addicted to their nursery. According to a psychiatrist friend of the Hadley's, the room and the house itself (which even ties the children's shoes for them) have replaced the Hadleys in their children's lives. However, the couple only finds out how serious this has become when George wants to lock the nursery and take his family for a vacation in the real world; his children become hysterical and end up trapping George and his wife in the nursery, where a pack of holographic African lions kills them.
This is eerily similar to another short story, I Hope I Shall Arrive Soon in which a man is in faulty cryogenic stasis and at his ship's computer's mercy. In both stories, the machines have become more than they were designed to be, and have somehow evolved an artificial intelligence that is concerned with self preservation. In The Veldt, the nursery has become able to create things that are real and not just illusions of real things, and uses its new ability to defend itself from its potential destroyers. Even though the children ordered the room to kill their real parents, it should not have been able to comply to this homicidal request. In I Hope I Shall Arrive Soon, the ship stopped following its programming, which stated that anyone who is conscious during a cryogenic journey has to be fed sensory information to keep the brain from degrading by feeding sensations from the subject's subconscious memory; instead it started to loop the same fictional scene to the main character over and over again, until he became unable to distinguish between what was real and what was simply a digital illusion.
In both short-stories, something that was supposed to be an illusion became corporeal: Whether it became such a perfect copy that it was impossible to discern any difference or because the machine was able to give life to its output is unimportant, since both have come to replace reality for those involved.