The Dark Somnium
This Creepypasta Scary Story, is from the nosleep subreddit, Written by Sam Marduk, make sure to check out the original story and support the author:
"Prison is hell" https://www.reddit.com/r/nosleep/comments/5bb2lq/prison_is_hell/
En liten tjänst av I'm With Friends. Finns även på engelska.