re you searching for the craziest science fiction stories to get lost in for a spell? You've got company. Recently someone asked, “What is the most disturbing science fiction story you've ever read? It's probably I Have No Mouth, And I Must Scream by Harlan Ellison for me. 

“For those, who aren't familiar with it, the Americans, Russians, and Chinese had constructed supercomputers to manage their militaries. One became sentient, assimilated the other two, and obliterated humanity.”

“Only five humans survive, and the Computer makes them immortal so that he can torture them for eternity. His existence is an incredible anguish, so he's seeking revenge on humanity for his construction.” Here are the top-voted replies. 

1. The Sparrow by Mary Doria Russell  

“This book honestly haunts me at least once a week, and it's been a year since I finished it. So I couldn't bring myself to read the sequel,” one person admitted. “Man, that book has stuck with me like few others. That ending is bleak,” another confessed. 

“When trying to explain to people that sci-fi can be great literature, this book is my go-to evidence. And the follow-up, Children of God,” a third person commented. 

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2. A Scanner Darkly by Philip K. D.  

One user mentioned, “If you've ever been addicted to hard drugs or seen others in its grips, you'd probably really find A Scanner Darkly by Philip K. D. pretty disturbing and emotionally moving; I know I did.” “Reading it genuinely made me feel stoned. You can tell PKD had a lot of experience with drugs,” another person commented.